The Carrara or Luna marble quarries, which constituted the principal source from which statuary marble was derived even prior to the time of Augustus, and which will probably continue to do so until the quarries of Paros shall be reopened, are beds of calcareous sandstone — macigno — altered by Plutonic action, and occurring in the insulated mountain of Apuana, between gneiss-like mica and talcose schist.*

[footnote] *On the geognostic relations of Carrara ('The City of the Moon', Strabo, lib. v., p. 222), see Savi 'Osservazioni sui terreni antichi Toscani', in the 'Nuova Giornale de' Letterati di Pisa', and Hoffmann, in Karsten's 'Archiv fur Mineralogie', bd. vi., s. 258-263, as well as in his 'Geogn. Reise durch Italien', s. 244-265.

Whether at some points granular limestone may not have been formed in the interior of the earth, and been raised by gneiss and syenite to the surface, where it forms vein-like fissures,* is a question on which I can not hazard an opinion, owing to my own want of personal knowledge of the subject.

[footnote] *According to the assumption of an excellent and very experienced observer, Karl von Leonhard. See his 'Jahrbuch fur Mineralogie', 1834 s. 329, and Bernhard Cotta, 'Geognosie', s. 310.

p 264 According to the admirable observations of Leopold von Buch, the masses of dolomite found in Southern Tyrol, and on the Italian side of the Alps, present the most remarkable instance of metamorphism produced by massive eruptive rocks on compact calcareous beds. The formation of the limestone seems to have proceeded from the fissures which traverse it in all directions. The cavities are every where covered with rhomboidal crystals of magnesian bitter spar, and the whole formation, without any trace of strtification, or of the fossil remains which it once contained, consists only of a granular aggregation of crystals of dolomite. Talc laminae lie scattered here and there in the newly-formed rock, traversed by masses of serpentine. In the valley of the Fassa, dolomite rises perpendicularly in smooth walls of dazzling whiteness to a height of many thousand feet. It forms sharply-pointed conical mountains, clustered together in large numbers, but yet not in contact with each other. The contour of their forms recalls to mind the beautiful landscape with which the rich imagination of Leonardi da Vinci has embellished the back-ground of the portrait of Mona Lisa.

The geognostic phenomena which we are now describing, and which excite the imagination as well as the powers of the intellect, are the result of the action of augite porphyry manifested in its elevating, destroying, and transforming force.*

[footnote] *Leop. von Buch, 'Geognostische Briefe an Alex. von Humboldt', 1824, s. 86 and 82; also in the 'Annalen de Chemie', t. xxiii., p. 276, and in the 'Abhandl. der Berliner Akad. aus der Jahren 1822 'und' 1823, s. 83-136; Von Dechen, 'Geognosie.' s. 574-576.

The process by which limestone is converted into dolomite is not regarded by the illustrious investigator who first drew attention to the phenomenon as the consequence of the tale being derived from the black porphyry, but rather as a transformatiion simultaneous with the appearance of this erupted stone through wide fissures filled with vapors. It remains for future inquirers to determine how transformation can have been effected without contact with the endogenous stone, where strata of dolomite are found to be interspersed in imestone. Where, in this case, are we to seek the concealed channels by which the Plutonic action is conveyed? Even here it may not, however, be necessary, in conformity with the old Roman adage, to believe "that much that is alike in nature may have been formed in wholly different ways." When we find, over widely extended parts of the earth, that two phenomena are always associated together, as, for instance, the occurrence of melaphyre p 265 and the transformation of compact limestone into a crystaline mass differing in its chemical character, we are, to a certain degree, justified in believing, where the second phenomenon is manifested unattended by the appearance of the first, that this apparent contradiction is owing to the absence, in certain cases, of some of the conditions attendant upon the exciting causes. Who would call in question the volcanic nature and igneous fluidity of basalt merely because there are some rare instances in which basaltic veins, traversing beds of coal or strata of sandstone and chalk, have not materially deprived the coal of its carbon, nor broken and slacked the sandstone, not converted the chalk into granular marble? Wherever we have obtained even a faint light to guide us in the obscure domain of mineral formation, we ought not ungratefully to disregard it, because there may be much that is still unexplained in the history of the relations of the transitions, or in the isolated interposition of beds of unaltered strata.

After having spoken of the alteration of compact carbonate of lime into granular limestone and dolomite, it still remains for us to mention a third mode of transformation of the same mineral, which is ascribed to the emission, in the ancient periods of the world, of the vapors of sulphuric acid. This transformation of limestone into gypsum is analogous to the penetration of rock salt and sulphur, the latter being deposited from sulphureted aqueous vapor. In the lofty Cordilleras of Quindin, far from all volcanoes, I have observed deposits of sulphur in fissures in gneiss, while in Sicily (at Cattolica, near Girgenti), sulphur, gypsum, and rock salt belong to the most recent secondary strata, the chalk formations.*

[footnote] *Horrman, 'Geogn. Reise', edited by Von Dechen, s. 113-119, and 380-386; Poggend., 'Annalen der Physik', bd. xxvi., s. 41.

I have also seen on the edge of the crater of Vesuvius, fissures filled with rock salt, which occurred in such considerable masses as occasionally to lead to its being disposed of by contraband trade. On both declivities of the Pyrenees, the connection of diorite and pyroxene, and colomite, gypsum, and rock salt, can not be questioned;* and here, as in the other phenomena which we have been considering, every thing bears evidence of the action of subterranean forces on the sedimentary strata of the ancient sea.

[footnote] *Dufrenoy, in the 'Memoires Geologiques', t. ii., p. 145 and 179.

There is much difficulty in explaining the origin of the beds of pure quartz, which occur in such large quantities in South America, and impart so peculiar a character to the chain of p 266 the Andes.*

[footnote] *Humboldt, 'Essai Geogn. sur le Gisement des Roches', p. 93; 'Asie Centrale', t. iii., p. 532.

In descending toward the South Sea, from Caxamarca toward Guangamarca, I have observed vast masses of quartz, from 7000 to 8000 feet in height, superposed sometimes on porphyry devoid of quartz, and sometimes on diorite. Can these beds have been transformed from sandstone, as Elie de Beaumont conjectures in the case of the quartz strata on the Col de la Poissonniere, east of Brian�on?*

[footnote] *Elie de Beaumont, in the 'Annales des Sciences Naturelles', t. xv., p. 362; Murchison, 'Silurian System', p. 286.

In the Brazils, in the diamond district of Minas Geraes and St. Paul, which has recently been so accurately investigated by Clausen, Plutonic action has developed in dioritic veins sometimes ordinary mica, and sometimes specular iron in quartzose itacolumite. The diamonds of Grammagoa are imbedded in strata of solid silica, and are occasionally enveloped in laminae of mica, like the garnets found in mica slate. The diamonds that occur furthest to the north, as those discovered in 1829 at 58 degrees lat., on the European slope of the Uralian Mountains, bear a geognostic relation to the black carboniferous dolomite of Adolffskoi* and to augitic porphyry, although more accurate observations are required in order fully to elucidate this subject.

[footnote] *Rose, 'Reise nach dem Ural', bd. i., s. 364 und 367.

Among the most remarkable phenomena of contact, we must, finally, enumerate the formation of garnets in argillaceous schist in contact with basalt and dolerite (as in Northumberland and the island of Anglesea), and the occurrence of a vast number of beautiful and most various crystals, as garnets, vesuvian, augite, and ceylanite, on the surfaces of contact between the erupted and sedimentary rock, as, for instance, on the junction of the syenite of Monzon with dolomite and compact limestone.

[footnote] *Leop. von Buch, 'Briefe', s. 109-129. See also, Elie de Beaumont 'On the Contact of Granite with the Beds of the Jura', in the 'Mem. Geol.' t. ii., p. 408.

In the island of Elba, masses of serpentine, which perhaps nowhere more clearly indicate the character of erupted rocks, have occasioned the sublimation of iron glance and red oxyd of iron in fissures of calcareous sandstone.

[footnote] *Hoffman, 'Reise', s. 30 und 37.

We still daily find the same iron glance formed by sublimation from the vapors and the walls of the fissures of open veins on the margin of the crater, and in the fresh lava currents of the volcanoes of Stromboli, Vesuvius, and AEtna.*

[footnote] *On the chemical process in the formation of specular iron, see Gay Lussac, in the 'Annales de Chimie', t. xxii., p. 415, and Mitscherlich, in Poggend., 'Annalen', bd. xv., s. 630. Moreover, crystals of olivine have been formed (probaby by sublimation) in the cavities of the obsidian of Cerro del Jacal, which I brought from Mexico (Gustav Rose, in Poggend., 'Annalen', bd. x., s. 323). Hence olivine occurs in basalt, lava, obsidian, artificial scoriae in meteoric stones, in the syenite of Elfdale, and (as hyalosiderite) in the wacke of the Kaiserstuhl.

The veins that p 267 are thus formed beneath our eyes by volcanic forces, where the contiguous rock has already attained a certain degree of solidification, show us how, in a similar manner, mineral and metallic veins may have been every where formed in the more ancient periods of the world, where the solid but thinner crust of our planet, shaken by earthquakes, and rent and fissured by the change of volume to which it was subjected in cooling, may have presented many communications with the interior, and many passages for the escape of vapors impregnated with earthy and metallic substances. The arrangement of the particles in layers parallel with the margins of the beins, the regular recurrence of analogous layers on the opposite sides of the veins (on their different walls), and, finally, the elongated cellular cavities in the middle, frequently afford direct evidence of the Plutonic process of sublimation in metalliferous veins. As the traversing rocks must be of more recent origin than the traversed, we learn from the relations of stratification existing between the porphyry and the argentiferous ores in the Saxon mines (the richest and most important in Germany), that these formations are at any rate more recent than the vegetable remains found in carboniferous strata and in the red sandstone.*

[footnote] *Constantin von Veust, 'Ueber die Porphyrgebilde', 1835, s. 89-96; also his 'Belenchtung der Werner'schen Gangtheorie', 1840, s. 6; and C. von Wissenbach, 'Abbildungen merkwurdiger Gangverhaltnisse', 1836, fig. 12. The ribbon-like structure of the veins is, however, no more to be regarded of general occurrence than the periodic order of the different members of these masses.

All the facts connected with our geological hypotheses on the formation of the earth's crust and the metamorphism of rocks have been unexpectedly elucidated by the ingenious idea which led to a comparison of the slags or scoriae of our smelting furnaces with natural minerals, and to the attempt of reproducing the latter from their elements.*

[footnote] *Mitscherlich, 'Ueber die kunstliche Darstellung der Mineralien', in the 'Abhandl. der Akademie der Wiss. zu Berlin', 1822-3, s. 25-41.

In all these operations, the same affinities manifest themselves which determine chemical combinations both in our laboratories and in the interior of the earth. The most considerable part of p 268 the simple minerals which characterize the more generally diffused Plutonic and erupted rocks, as well as those on which they have exercised a metamorphic action, have been produced in a crystalline state, and with perfect identify, in artificial mineral products. We must, however, distinguish here between the scoriae accidentally formed, and those which have been designedly produced by chemists. To the former belong feldspar, mica, augite, olivine, hornblende, crystallized oxyd of iron, magnetic iron in octahedral crystals, and metallis titanium;* to the latter, garnets, idocrase, rubies (equal in hardness to those found in the East), olivine, and augite.**

[footnote] *In scoriae crystals of feldspar have been discovered by Heine in the refuse of a furnace for copper fusing, near Sangerhausen, and analyzed by Kersten (Poggend., 'Annalen', bd. xxxiii., s. 337); crystals of augite in scoriae at Sahle (Mitscherlich, in the 'Abhandl. der Akad. zu Berlin', 1822-23, s. 40); of oliving by Seifstrom (Leonhard, 'Basalt-Gebilde', bd. ii., s. 495); of mica in old scoriae of Schloss Garpenberg (Mitscherlich, in Leonhard, op. cit., s. 506); of magnetic iron in the scoriae of Chatillon sur Seine (Leonhard, s. 441); and of micaceous iron in potter's clay (Mitscherlich, in Leohnard, op. cit., s. 234). [See Ebelmer's papers in 'Ann. de Chimie et de Physique', 1847; also 'Report on the Crystalline Slags', by John Percy, M.D., F.R.S., and William Hallows Miller, M.A., 1847. Dr. Percy, in a communication with which he has kindly favored me, says that the minerals which he has found artificially produced and proved by analysis are Humboldtilite, gehlenite, olivine, and magnetic oxyd of iron, in octahedral crystals. He suggests that the circumstance of the production of gehlenite at a high temperature in an iron furnace may possibly be made available by geologists in explaining the formation of the rocks in which the natural mineral occurs, as in Fassathal in the Tyrol.] — Tr.

[footnote] **Of minerals purposely produced, we may mention idocrase and garnet (Mitscherlich, in Poggend., 'Annalen der Physik', bd. xxxii., s. 340); ruby (Gaudin, in the 'Comptes Rendus de l'Academie de Science', t. iv., Part i., p. 999); olivine and augite (Mitscherlich and Berthier, in the 'Annales de Chimie et de Physique', t. xxiv., p. 376). Notwithstanding the greatest possible similarity in crystalline form, and perfect identity in chemical composition, existing, according to Gustav Rose, between augite and hornblende, hornblende has never been found accompanying augite in scoriae, nor have chemists ever succeeded in artificially producing either hornblende or feldspar (Mitscherlich in Poggend., 'Annalen', bd. xxxiii., s. 340, and Rose, 'Reise nach dem Ural', bd. ii., s. 358 und 363). See also, Beaudant, in the 'Mem. de l'Acad. des Sciences', t. viii., p. 221, and Becquerel's ingenious experiments in his 'Trait de l'Electricite,' t. i., p. 334; t. iii., p. 218; and t. v., p. 148 and 185.

These minerals constitute the main constituents of granite, gneiss, and mica schist, of basalt, dolerite, and many porphyries. The artificial production of feldspar and mica is of most especial geognostic importance with reference to the theory of the formation of gneiss by the metamorphic agency of argillaceous schist, which contains all the constituents of granite, p 269 potash not excepted.*

[footnote] *D'Aubuisson, in the 'Journal de Physique', t. lxviii., p. 128.

It would not be very surprising, therefore, as is well observed by the distinguished geognosist, Von Dechen, if we were to meet with a fragment of gneiss formed on the walls of a smelting furnace which was built of argillaceous slate and graywacke.

After having taken this general view of the three classes of erupted, sedimentary, and metamorphic rocks of the earth's crust, it still remains for us to consider the fourth class, comprising 'conglomerates', or 'rocks of detrius'. The very term recalls the destruction which the earth's crust has suffered, and likewise, perhaps reminds us of the process of cementation, which has connected together, by means of oxyd of iron, or of some argillaceous and calcareous substances, the sometimes rounded and sometimes angular portions of fragments. Conglomerates and rocks of detritus, when considered in the widest sense of the term, manifest characters of a double origin. The substances which enter into their mechanical composition have not been alone accumulated by the action of the waves of the sea or currents of fresh water, for there are some of these rocks the formation of which can not be attributed to the action of water. "When basaltic islands and trachytic rocks rise on fissures, friction of the elevated rock against the walls of the fissures causes the elevated rock to be inclosed by conglomerates composed of its own matter. The granules composing the sandstones of many formations have been separated rather by friction against the erupted volcanic or Plutonic rock than destroyed by the erosive force of a neighboring sea. The existence of these friction 'conglomerates', which are met with in enormous masses in both hemispheres, testifies the intensity of the force with which the erupted rocks have been propelled from the interior through the earth's crust. This detritus has subsequently been taken up by the waters, which have then deposited it in the strata which it still covers."*

[footnote] *Leop. von Buck, 'Geognost. Briefe', s. 75-82, where it is also shown why the new red sandstone (the 'Todtliegende' of the Thuringian flotz formation) and the coal measures must be regarded as produced by erupted porphyry.

Sandstone formations are found imbedded in all strata, from the lower silurian transition stone to the beds of the tertiary formations, superposed on the chalk. They are found on the margin of the boundless plains of the New Continent, both within and without the tropics, extending like breast-works along the ancient shore, against which the sea once broke its foaming waves.

p 270 If we cast a glance on the geographical distribution of rocks, and their relations in space, in that portion of the earth's crust which is accessible to us, we shall find that the most universally distributed chemical substance is 'silicic acid', generally in a variously-colored and opaque form. Next to solid silicic acid we must reckon carbonate of lime, and then the combinations of silicic acid with alumina, potash, and soda, with lime, magnesia, and oxyd of iron.

The substances which we designate as 'rocks' are determinate associations of a small number of minerals, in which some combine parasitically, as it were, with others, but only under definite relations; thus, for instance, although quartz (silica), feldspar, and mica are the principal constituents of granite, these minerals also occur, either individually or collectively, in many other formations. By way of illustrating how the quantitative relations of one feldspathic rock differ from another, richer in mica than the former, I would mention that, according to Mitscherlich, three times more alumina and one third more silica than that ossessed by feldspar, give the constituents that enter into the composition of mica. Potash is contained in both — a substance whose existence in many kinds of rocks is probably antecedent to the dawn of vegetation on the earth's surface.

The order of succession, and the relative age of the different formations, may be recognized by the superposition of the sedimentary, metamorphic, and conglomerate strata; by the nature of the formations traversed by the erupted masses, and — with the greatest certainty — by the presence of organic remains and the differences of their structure. The application of botanical and zoological evidence to determine the relative age of rocks — this chronometry of the earth's surface, which was already present to the lofty mind of Hooke — indicates one of the most glorious epochs of modern geognosy, which has finally, on the Continent at least, been emancipated from the sway of Semitic doctrines. Palaeontological investigations have imparted a vivifying breath of grace and diversity to the science of the solid structure of the earth.

The fossiliferous strata contain, entombed within them, the floras and faunas of by-gone ages. We ascend the stream of time, as in our study of the relations of superposition we descend deeper and deeper through the different strata, in which lies revealed before us a past world of animal and vegetable life. Far-extending disturbances, the elevation of great mountain chains, whose relative ages we are able to define, attest the p 271 destruction of ancient and the manifestation of recent organisms. A few of these older structures have remained in the midst of more recent species. Owing to the limited nature of our knowledge of existence, and from the figurative terms by which we seek to hide our ignorance, we apply the appellation 'recent structure' to the historical henomena of transition manifested in the organisms as well as in the forms of primitive seas and of elevated lands. In some cases these organized structures have been preserved perfect in the minutest details of tissues, integument, and articulated parts, while in others, the animal, passing over soft argillaceous mud, has left nothing but the traces of its course,* or the remains of its undigested food, as in the coprolites.**

[footnote] *[In certain localities of the new red sandstone, in the Valley of the Connecticut, numerous tridactyl markings have been occasionally observed on the surface of the slabs of stone when split asunder, in like manner as the ripple-marks appear on the successive layers of sandstone in Tilgate Forest. Some remarkably distinct impressions of this kind, at Turner's Falls (Massachusetts), happening to attract the attention of Dr. James Deane, of Greenfield, that sagacious observer was struck with their resemblance to the foot-marks left on the mud-banks of the adjacent river by the aquatic birds which had recenty frequented the spot. The specimens collected were submitted to Professor G. Hitchcock, who followed up the inquiry with a zeal and success that have led to the most interesting results. No reasonable doubt now exists that the imprints in question have been produced by the tracks of bipeds impressed on the stone when in a soft state. The announcement of this extraordinary phenomenon was first made by Professor Hitchcock, in the 'American Journal of Science' (January, 1836), and that eminent geologist has since published full descriptions of the different species of imprints which he has detected, in his splendid work on the geology of Massachusetts. — Mantell's 'Medals of Creation', vol. ii., p. 310. In the work of Dr. Mantell above referred to, there is, in vol. ii., p. 815, an admirable diagram of a slab from Turner's Falls, covered with numerous foot-marks of birds, indicating the track of ten or twelve individuals of different sizes.] — Tr.

[footnote] **[From the examination of the fossils spoken of by geologists under the name of 'Coprolites', it is easy to determine the nature of the food of the animals, and some other points; and when, as happened occasionally, the animal was killed while the process of digestion was going on, the stomach and intestines being partly filled with half-digested food, and exhibiting the coprolites actually 'in situ', we can make out with certainty not only the true nature of the food, but the proportionate size of the stomach, and the length and nature of the intestinal canal. Within the cavity of the rib of an extinct animal, the palaeontologist thus finds recorded, in indelible characters, some of those hieroglyphics upon which he founds his history. — 'The Ancient World', by D. T. Ansted, 1847, p. 173.] — Tr.

In the lower Jura formations (the lias of Lyme Regis), the ink bag of the sepia has been so wonderfully preserved, that the material, which myriads p 272 of years ago might have served the animal to conceal itself from its enemies, still yields the color with which its image may be drawn.*

[footnote] *A discovery made by Miss Mary Anning, who was likewise the discoverer of the coprolites of fish. These coprolites, and the excrements of the Ichthyosauri, have been found in such abundance in England (as, for instance, near Lyme Regis), that, according to Buckland's expression, they lie like potatoes scattered in the ground. See Buckland, 'Geology considered with reference to Natural Theology', vol. i., p. 188-202 and 305. With respect to the hope expressed by Hooke "to raise a chronology" from the mere study of broken and fossilized shells "and to state the interval of time wherein such or such castrophes and mutations have happened," see his 'Posthumous Works, Lecture', Feb. 29, 1688. [Still more wonderful is the preservation of the substance of the animal of certain Cephalopodes in the Oxford clay. In some specimens recently obtained, and described by Professor Owen, not only the ink bag, but the muscular mantle, the head, and its crown of arms, are all preserved in connection with the belemnite shell, while one specimen exhibits the large eyes and the funnel of the animal, and the remains of two fins, in addition to the shell and the ink bag. See Ansted's 'Ancient World', p. 147.] — Tr.

In other strata, again, nothing remains but the faint impression of a muscle shell; but even this, if it belong to a main dividion of mollusca,* may serve to show the traveler, in some distant land, the nature of the rock in which it is found, and the organic remains with which it is associated.

[footnote] *Leop. von Buch, in the 'Abhandlungen der Akad. der Wiss. zu Berlin in dem Jahr' 1837, s. 64.

Its discovery gives the history of the country in which it occurs.

The analytic study of primitive animal and vegetable life has taken a double direction: the one is purely morphological, and embraces, especially, the natural history and physiology of organisms, filling up the chasms in the series of still living species by the fossil structures of the primitive world. The second is more specially geognostic, considering fossil remains in their relations to the superposition and relative age of the sedimentary formations. The former has long predominated over the latter, and an imperfect and superficial comparison of fossil remains with existing species has led to errors, which may still be traced in the extraordinary names applied to certain natural bodies. It was sought to identify all fossil species with those still extant in the same manner as, in the sixteenth century, men were led by false analogies to compare the animals of the New Continent with those of the Old. Peter Camper, Sommering, and Blumenbach had the merit of being the first, by the scientific application of a more accurate p 273 comparative anatomy, to throw light on the osteological branch of palaeontology — the archaeology of organic life; but the actual geognostic views of the doctrine of fossil remains, the felicitous combination of the zoological character with the order of succession, and the relative ages of strata, are due to the labors of George Cuvier and Alexander Brongniart.

The ancient sedimentary formations and those of transition rocks exhibit, in the organic remains contained within them, a mixture of structures very variously situated on the scale of progressively-developed organisms. These strata contain but few plants, as, for instance, some species of Fuci, Lycopodiaceae which were probably arborescent, Equisetaceae, and tropical ferns; they present, however, a singular association of animal forms, consisting of Crustacea (trilobites with reticulated eyes, and Calymene), Brachiopoda ('Spirifer, Orthis'), elegant Sphaeronites, nearly allied to the Crinoidea,* Orthoceraitites, of the family of the Cephalopoda, corals, and, blended with these low organisms, fishes of the most singular forms, imbedded in the upper silurian formations.

[footnote] *Leop. von Buch, 'Gebirgsformationen von Russland', 1840, s. 24-50.

The family of the Cephalaspides, whose fragments of the species 'Pterichtys' were long held to be trilobites, belongs exclusively to the devonian period (the old red), manifesting, according to Agassiz, as peculiar a type among fishes as do the Ichthyosauri and Plesiosauri among reptiles.*

[footnote] *Agassiz, 'Monographie des Poissons Fossiles du vieux Gres Rouge', p. vi. and 4.

The Goniatites, of the tribe of Ammonites,* a are manifested in the transition chalk, in the graywacke of the devonian periods, and even in the latest silurian formations.

[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1838, s. 149-168; Beyrich, 'Beitr. zur Kenntniss des Rheinischen Uebergangagebirges', 1837, s. 45.

The dependence of physiological gradation upon the age of the formations, which has not hitherto been shown with perfect certainty in the case of invertebrata,* is most regularly manifested in vertebrated animals.

[footnote] *Agassiz, 'Recherches sur les Poissons Fossiles', t. i., 'Introd.', p. xviii.; Davy, 'Consolation in Travel', dial. iii.

The most ancient of these, as we have already seen, are fishes; next in the order of succession of formation, passing from the lower to the upper, come reptiles and mammalia. The first reptile (a Saurian, the Monitor of Cuvier), which excited the attention of Leibnitz,* is found in cuperiferous schist of the Zechstein of Thuringa; the Palaeosaurus and Thecodontosaurus of Bristol are, according to Murchison, of the same age.

[footnote] *A Protosaurus, according to Hermann von Meyer. The rib of a Saurian asserted to have been found in the mountain limestone (carbonate of lime) of Northumberland (Herm. von Meyer, 'Palaeologica', s. 299), is regarded by Lyell ('Geology', 1832, vol. i., p. 148) as very doubtful. The discoverer himself referred it to the alluvial strata which cover the mountain limestone.

The Saurians are found in large numbers in the muschelkalk,* in the keuper, and in the oolitic formations, where they are the most numerous.

[footnote] *F. von Alberti, 'Monographie des Bunten Sandsteins, Muschelkalks und Keupers', 1834, s. 119 und 314.

At the period of these formations there existed Pleiosauri, having long, swan-like necks consisting of thirty vertebrae; Megalosauri, monsters resembling the crocodile, forty-five feet in length, and having feet whose bones were like those of terrestrial mammalia, eight species of large-eyed Ichthyosauri, the Geosaurus or 'Lacerta gigantea', of Sommering, and finally, seven remarkable species of Pterodactyles,* of Saurians furnished with membranous wings.

[footnote] *See Hermann von Meyer's ingenious considertions regarding the organization of the flying Saurians, in his 'Palaeologica', s. 228-252. In the fossil specimen of the Pterodactylus crassirostris, which, as well as the loonger known P. longirostris (Ornithocephalus of Sommering), was found at Solenhofen, in the lithographic slate of the upper Jura formation, Professor Goldfuss has even discovered traces of the membranous wing, "with the impressions of curling tufts of hair, in some places a full inch in length."

In the chalk the number of the crocodilial Saurians diminishes, although this epoch is characterized by the so-called crocodile of Maestricht (the Mososaurus of Conybeare), and the colossal, probably graminivorous Iguandon. Cuvier has found animals belonging to the existing families of the crocodile in the tertiary formation, and Scheuchzer's 'antediluvian man' ('homo diluvii testis'), a large salamander allied to the Axolotl, which I brought with me from the large Mexican lakes, belongs to the most recent fresh-water formations of Oeningen.*

[footnote] *[Ansted's 'Ancient World', p. 56.] — Tr.

The determination of the relative ages of organisms by the superposition of the strata has led to important results regarding the relations which have been discovered between extinct families and species (the latter being but few in number) and those which still exist. Ancient and modern observations concur in showing that the fossil floras and faunas differ more from the present vegetable and animal forms in proportion as they belong to lower, that is, more ancient sedimentary formations. The numerical relations first deduced by Cuvier p 275 from the great phenomena of the metamorphism of organic life,* have led, through the admirable labors of Deshayes and Lyell, to the most marked results, especially with reference to the different groups of the tertiary formations, which contain a considerable number of accurately investigated structures.

[footnote] *Cuvier, 'Recherches sur les Ossemens Fossiles', t. i., p. 52-57. See, also, the geological scale of epochs in Phillips's 'Geology', 1837, p. 166-185.

Agassiz, who has examined 1700 species of fossil fishes, and who estimates the number of living species which have either been described or are preserved in museums at 8000, expressly says, in his masterly work, that, "with the exception of a few small fossil fishes peculiar to the argillaceous geodes of Greenland, he has not found any animal of this class in all the transition, secondary or tertiary formations, which is specifically identical with any still extant fish." He subjoins the important observation "that in the lower tertiary formations, for instance, in the coarse granular calcareous beds, and in the London clay,* one third of the fossil fishes belong to wholly extinct families.

[footnote] *[See 'Wonders of Geology', vol. i., p. 230.] — Tr.

Not a single species of a still extant family is to be found under the chalk, while the remarkable family of the 'Sauroidi' (fishes with enameled scales), almost allied to reptiles, and which are found from the coal beds — in which the larger species lie — to the chalk, where they occur individually, bear the same relation to the two families (the Lepidosteus and Polypterus) which inhabit the American rivers and the Nile, as our present elephants and tapirs do to the Mastodon and Anaplotheriun of the primitive world."*

[footnote] *Agassiz, 'Poissons Fossiles', t. i., p. 30, and t. iii., p. 1-52; Buckland, 'Geology', vol. i., p. 273-277.

The beds of chalk which contain two of these sauroid fishes and gigantic reptiles, and a whole extinct world of corals and muscles, have been proved by Ehrenberg's beautiful discoveries to consist of microscopic Polythalamia, many of which still exist in our seas, and in the middle latitudes of the North Sea and Baltic. The first group of tertiary formations above the chalk, which has been designated as belonging to the 'Eocene Period', does not, therefore, merit that designation, since "the 'dawn of the world' in which we live extends much further back in the history of the past than we have hitherto supposed."*

[footnote] *Ehrenberg, 'Ueber noch jetzt lebende Thierarten der Kreidelnldung', in the 'Abhandl. der Berliner Akad.', 1839, s. 164.

As we have already seen, fishes, which are the most ancient of all vertebrata, are found in the silurian transition strata, p 276 and then uninterruptedly on through all formations to the strata of the tertiary period, while Saurians begin with the zechstone. In like manner, we find the first mammalia ('Thylacotherium Prevostii', and 'T. Bucklandii', which are nearly allied according to Valenciennes,* with marsupial animals) in the oolitic formations (Stonesfield schist), and the first birds in the most ancient cretaceous strata.**

[footnote] *Valenciennes, in the 'Comptes Rendus de l'Academie des Sciences', t. vii., 1838, Part ii., p. 580.

[footnote] **In the Weald clay; Bendant, 'Geologie', p. 173. The ornitholites increase in number in the gypsum of the tertiary formations. Cuvier, 'Ossemens Fossiles', t. ii., p. 302-328.

Such are, according to the present state of our knowledge, the lowest* limits of fishes, Saurians, mammalia, and birds.

[footnote] *[Recent collections from the southern hemisphere show that this distribution was not so universal during the earlier epochs as has generally been supposed. See papers by Darwin, Sharpe, Morris, and McCoy, in the 'Geological Journal'.] — Tr'.

Although corals and Serpulidae occur in the most ancient formations simultaneously with highly-developed Cephalopodes and Crustaceans, thus exhibiting the most various orders grouped together, we yet discover very determinate laws in the case of many individual groups of one and the same orders. A single species of fossil, as Goniatites, Trilobites, or Nummulites, sometimes constitutes whole mountains. Where different families are blended together, a determinate succession of organisms has not only been observed with reference to the superposition of the formations, but the association of certain families and species has also been noticed in the lower strata of the same formation. By his acute discovery of the arrangement of the lobes of their chamber-sutures, Leopold von Buch has been enabled to divide the innumerable quantity of Ammonites into well-characterized families, and to show that Ceratites appertain to the muschelkalk, Arietes to the lias, and Goniatites to transition limestone and graywacke.*

[footnote] *Leop. von Buch, in the 'Abhandl. der Berl. Akad.', 1830, s. 135-187.

The lower limits of Belemnites are, in the keuper, covered by Jura limestone, and their upper limits in the chalk formations.*

[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 135.

It appears, from what we now know of this subject, that the waters must have been inhabited at the same epoch, and in the most widely-remote districts of the world, by shell-fish, which were at any rate, in part, identical with the fossil remains found in England. Leopold von Buch has discovered exogyra and trigonia in the southern hemisphere (volcano of p 277 Maypo in Chili), and D'Orbigny has described Ammonites and Gryphites from the Himalaya and the Indian plains of Cutch, these remains being identical with those found in the old Jurassic sea of Germany and France.

The strata which are distinguished by definite kinds of petrifacations, or by the fragments contained within them, form a geognostic horizon, by which the inquirer may guide his steps, and arrive at certain conclusions regarding the identity or relative age of the formations, the periodic recurrence of certain strata, their parallelism, or their total suppression. If certain strata, their parallelism, or their total suppression. If we classify the type of the sedimentary structures in the simplest mode of generalization, we arrive at the following series in proceeding from below upward: 1. The so-called 'transition rocks', in the two divisions of upper and lower graywacke (silurian and devonian systems), the latter being formerly designated as old red sandstone. 2. The 'lower trias',* comprising mountain limestone, coal-measures, together with the lower new red sandstone (Todtliegende and Zechstein).** 3. The 'upper trias', including variegated sandstone,** muschelkalk, and keuper. 4. 'Jura limestone' (lias and oolite). 5. 'Green sandstone', the quader sanstein, upper and lower chalk, terminating the secondary formations, which begin with limestone. 6. 'Tertiary formations' in three divisions, distinguished as granular limestone, the lignites, and the sub-Apennine gravel of Italy.

[footnote] *Quenstedt, 'Flotzgebirge Wurtembergs', 1843, s. 13.

[footnote] ** Murchison makes two divisions of the 'bunter sandstone', the upper being the same as the 'trias' of Alberti, while the lower division, to which the 'Vosges sandstone' of Elie de Beaumont belongs — the 'zeckstein' and the 'todtliegende' — he forms his 'Permian' system. He makes the secondary formations commence with the 'upper trias', that is to say, with the upper division of our (German) bunter sandstone, while the Permian system, the carboniferous or mountain limestone, and the devonian and silurian strata, constitute his 'palaeozoic formatiions'. According to these views, the chalk and Jura constitute the upper, and the keuper, the muschelkalk, and the bunter sandstone the lower secondary formations, while the Permian system and the carboniferous limestone are the upper, and the devonian and silurian strata are the lower palaeooic formation. The fundamental principles of this general classification are developed in the great work in which this indefatigable British geologist purposes to describe the geology of a large part of Eastern Europe.

Then follow, in the alluvial beds, the colossal bones of the mammalia of the primitive world, as the mastodon, dinothrium p 278 missurium, and the megatherides, among which is Owen's sloth-like mylodon, eleven feet in the length.*

[footnote] *[See Mantell's 'Wonders of Geology', vol. i., p. 168.] — Tr.

Besides these extinct families, we find the fossil remains of still extant animals, as the elephant, rhinoceros, ox, horse, and stag. The field near Bogota, called the 'Campo de Gigantes', which is filled with the bones of mastodons, and in which I caused excavations to be made, lies 8740 feet above the level of the sea, while the osseous remains, found in the elevated plateaux of Mexico, belong to true elephants of extinct species.*

[footnote] *Cuvier, 'Ossemens Fossiles', 1821, t. i., p. 157, 261, and 264. See, also, Humboldt, 'Ueber die Hochebene von Bogota', in the 'Deutschen Vierteljahrs-schrift', 1839, bd. i., s. 117.

The projecting spurs of the Himalaya, the Sewalik Hills, which have been so zealously investigated by Captain Cantley* and Dr. Falconer, and the Cordilleras, whose elevations are probably, of very different epochs, contain, besides numerous mastodons, the sivatherium, and the gigantic land tortoise of the primitive world ('Colossochelys'), which is twelve feet in length and six in height, and several extant families, as elephants, rhinoceroses, and giraffes; and it is a remarkable fact, that these remains are found in a zone which still enjoys the same tropical climate which must be supposed to have prevailed at the period of the mastodons.**

[footnote] *[The fossil fauna of the Sewalik range of hills, skirting the southern base of the Himalaya, has proved more abundant in genera and species of mammalia than that of any other region yet explored. As a general expression of the leading features, it may be stated, that it appears to have been composed of representative forms of all ages, from the 'oldest of the tertiary period down to the modern', and of 'all the geographical' divisions of the Old Continent grouped together into one comprehensive fauna. 'Fauna Antiqua Sivaliensis', by Hugh Falconer, M.D., and Major P. T. Cautley.] — Tr.

Having thus passed in review both the inorganic formations of the earth's crust and the animal remains which are contained within it, another branch of the history of the organic life still remains for our consideration, viz., the epoch of vegetation, and the successive floras that have occurred simultaneously with the increasing extent of the dry land and the modifications of the atmosphere. The oldest transition strata, as we have already observed, contain merely cellular marine plants, and it is only in the devonian system that a few cryptogamic forms of vascular plants (Calamites and Lycopodiaceae) have been observed.*

[footnote] *Beyrich, in Karsteu's 'Archiv fur Mineralogie', 1844, bd. xviii., s. 218.

Nothing appears to corroborate p 279 the theoretical views that have been started regarding the simplicity of primitive forms of organic life, ow that vegetable preceded animal life, and that the former was necessarily dependent upon the latter. The existence of races of men inhabiting the icy regions of the North Polar lands, and whose nutriment is solely derived from fish and cetaceans, shows the possibility of maintaining life independently of vegetable substances. After the devonian system and the mountain limestone, we come to a formation, the botanical analysis of which has made such brilliant advances in modern times.*

[footnote] *By the important labors of Count Sternberg, Adolphe Brongniart, Goppert, and Lindley.

The coal measures contain not only fern-like cryptogamic plants and phanerogamic monocotyledons (grasses, yucc-like Liliaceae and palms), but also gymnospermic dicotyledons (Coniferae and Cycadeae), amounting in all to nearly 400 species, as characteristic of the coal formations. Of these we will only enumerate arborescent Calamites and Lycopodiaceae, scaly Lepidodendra, Sigillariae, which attain a height of sixty feet, and are sometimes found standing upright, being distinguished by a double system of vascular bundles, cactus-like Stigmariae, a great number of ferns, in some cases the stems, and in others the fronds alone being found, indicating by their abundance the insular form of the dry land,* Cycadeae** especially palms, although fewer in number.***

[footnote] *See Robert Brown's 'Botany of Congo', p. 42, and the Memoir of the unfortunate E'Urville, 'De la Distribution des Fougeres sur la Surface du Globe Terrestre'.

[footnote] **Such are the Cycadeae discovered by Count Sternberg in the old carboniferous formation at Radnitz, in Bohemia, and described by Corda (two species of Cycatides and Zamites Cordai. See Goppert, 'Fossile Cycadeen in den Arbeiten der Schles. Gesellschaft, fur waterl. Cultur im Jahr' 1843, s. 33, 37, 40 and 50). A Cycadea (Pterophyllum gonorchachis, Gopp.) has also been found in the carboniferous formations in Upper Silesia, at Konigshutte.

[footnote] ***Lindley, 'Fossil Flora', No. xv., p. 163.

Asterophyllites, having whorl-like leaves, and allied to the Naiades, with araucaria-like Coniferae',* which exhibit faint traces of annual rings.

[footnote] *'Fossil Coniferae', in Buckland's 'Geology', p. 483-490. Witham has the great merit of having first recognized the existence of Coniferae in the early vegetation of the old carboniferous formation. Almost all the trunks of trees found in this formation were previously regarded as palms. The species of the genus 'Araucaria' are, however, not peculiar to the coal formations of the British Islands; they likewise occur in Upper Silesia.

This difference of character from our present vegtation, minifested in the vegetative forms which were so luxuriously developed on the drier p 280 and more elevated portions of the old red sandstone, was maintained through all the subsequent epochs to the most recent chalk formations; amid the peculiar characteristics exhibited in the vegetable forms contained in the coal measures, there is, however, a strikingly-marked prevalence of the same families, if not of the same species,* in all parts of the earth as it then existed, as in New Holland, Canada, Greenland, and Melville Island.

[footnote[ *Adolphe Brongniart, 'Prodrome d'une Hist. des Vegetaux Fossiles', p. 179; buckland, 'Geology', p. 479; Endlicher and Unger, 'Grundzuge der Botanik', 1843, s. 455.

The vegetation of the primitive period exhibits forms which, from their simultaneous affinity with several families of the present world, testify that many intermediate links must have become extinct in the scale of organic development. Thus, for example, to mention only two instances, we would notice the Lepidodendra, which, according to Lindley, occupy a place between the Coniferae and the Lycopodiaceae*, and the Araucariae and pines, which exhibit some peculiarities in the union of their vascular bundles.

[footnote] *"By means of Lepidodendron, a better passage is established from flowering to flowerless plants than by either Equisetum or Cycas, or any other known genus." — Lindley and Hutton, 'Fossil Flora', vol. ii., p. 53.

Even if we limit our consideration to the present world alone, we must regard as highly important the discovery of Cycadeae and Coniferae side by side with Sagenariae and Lepidodendra in the ancient coal measures. The Coniferae are not ony allied to Cupuliferae and Betulinae, with which we find them associated in lignite formations, but also with Lycopodiaceae. The family of the sago-like Cycadeae approaches most nearly to palms in its external appearance, while these plants are specially allied to Coniferae in respect to the structure of their blossoms and seed.*

[footnote] *Kunth, 'Anordnung der Pflanzenfamilien', in his 'Handb. der Botanik', s. 307 und 314.

Where many beds of coal are superposed over one another, the families and species are not always blended, being most frequently grouped together in separate genera; Lycopodiaceae and certain ferns being alone found in one bed, and Stigmariae and Sigillariae in another. In order to give some idea of the luxuriance of the vegetation of the primitive world, and of the immense masses of vegetable matter which was doubtlessly accumulated in currents and converted in a moist condition into coal,* I would instance the Saarbrucker coal measures, p 281 where 120 beds are superposed on one another, exclusive of a great many which are less than a foot in thickness; the coal beds at Johnstone, in Scotland, and those in the Creuzot, in Burgundy, are some of them, respectively, thirty and fifty feet in thickness,** while in the forests of our temperate zones, the carbon contained in the trees growing over a certain area would hardly suffice, in the space of a hundred years, to cover it with more than a stratum of seven French lines in thickness.***

[footnote] That coal has not been formed from vegetable fibers charred by fire, but that it has more probably been produced in the moist way by the action of sulphuric acid, is strikingly demonstrated by the excellent observation made by Goppert (Karsten, 'Archiv fu Mineralogie', bd. xviii., s. 530), on the conversion of a fragment of amber-tree into black coal. The coal and the unaltered amber lay side by side. Regarding the part which the lower forms of vegetation may have had in the formation of coal beds, see Link, in the 'Abhandl. der Berliner Akademie der Wissenschaften', 1838, s. 38.

[footnote] **[The actual total thickness of the different beds in England varies considerably in different districts, but appears to amount in the Lancashire coal field to as much as 150 feet. — Ansted's 'Ancient World', p. 78. For an enumeration of the thickness of coal measures in America and the Old Continent, see Mantell's 'Wonders of Geology', vol. ii., p. 60.] — Tr.

[footnote] ***See the accurate labors of Chevandier, in the 'Comptes Rendus de l'Academie des Sciences', 1844, t. xviii., Part i., p. 285. In comparing this bed of carbon, seven lines in thickness, with beds of coal, we must not omit to consider the enormous pressure to which the latter have been subjected from superimposed rock, and which manifests itself in the flattened form of the stems of the trees found in these subterranean regions. "The so-called 'wood-hills' discovered in 1806 by Sirowatskoi, on the south coast of the island of New Siberia, consist, according to Hedenstrom, of horizontal strata of sandstone, aolternating with bituminous trunks of trees, forming a mound thirty fathoms in neight; at the summit the stems were in a vertical position. The bed of driftwood is visible at five wersts' distance." — See Wrangel, 'Reise Iangs der Nordkuste von Siberien, in den Jahren' 1820-24, th. i., s. 102.

Near the mouth of the Mississippi, and in the "wood hills" of the Siberian Polar Sea, described by Admiral Wrangel, the vast number of trunks of trees accumulated by river and sea water currents affords a striking instance of theenormous quantities of drift-wood which must have favored the formation of carboniferous deposition in the island waters and insular bays. There can be no doubt that these beds owe a considerable portion of the substances of which they consist to grasses, small branching shrubs, and cryptogamic plants.

The association of palms and Coniferae, which we have indicated as being characteristic of the coal formations, is discoverable throughout almost all formations to the tertiary period. In the present condition of the world, these genera p 282 appear to exhibit no tendency whatever to occur associated together. We have so accustomed ourselves, although erroneously, to regard Coniferae as a northern form, that I experienced a feeling of surprise when, in ascending from the shores of the South Pacific toward Chilpansingo and the elevated valleys of Mexico, between the 'Venta de la Moxonera' and the 'Alto de los Caxones', 4000 feet above the level of the sea, I rode a whole day through a dense wood of Pinus occidentalis, where I observed that these trees, which are so similar to the Weymouth pine, were associated with fan palms* ('Corypha dulcis'), swarming with brightly-colored parrots.

[[footnote] *This corypha is the 'soyate' (in Aztec, zoyatl), or the 'Palma dulce' of the natives. See Humboldt and Bonplaud, 'Synopsis Plant. AEquinoct. Orbis Novi', t. i., p. 302. Professor Buschmann, who is profoundly acquainted with the American languages, remarks, that the 'Palma soyate' is so named in Yepe's 'Vocabulario de la Lengua Othomi', and that the Aztec word zoyatl (Molina, 'Vocabulario en Lengua Mexicana y Castellana', p. 25) recurs in names of places, such as Zoyatitlan and Zoyapanco, near Chiapa.

South America has oaks, but not a single species of pine; and the first time that I again saw the familiar form of a fir-tree, it was thus associated with the strange appearance of the fan palm.*

[footnote] *Near Baracoa and Cayos de Moya. See the Admiral's journal of the 25th and 27th of November, 1492, and Humboldt, 'Examen Critique de l'Hist. de la Geographie du Nouveau Continent', t. ii., p. 252, and 5. iii., p. 23. Columbus, who invariably paid the most remarkable attention to all natural objects, was the first to observe the difference between 'Podocarpus' and 'Pinus'. "I find," said he, "en la tierra aspera del Cibao pinos que no Ilevan pinas (fir cones), pero portal orden compuestos por naturaleza, que (los frutos) parecen azeytunas del Axarafe de Sevilla." The great botanist, Richard, when he published his excellent Memoir on Cycadeae and Coniferae, little imagined that before the time of L'Heritier, and even before the end of the fifteenth century, a navigator had separated 'Podocarpus' from the Abietineae.

Christopher Columbus, in his first voyage of discovery, saw Coniferae and palms growing together on the northeastern extremity of the island of Cuba, likewise within the tropics, and scarcely above the level of the sea. This acute observer, whom nothing escaped, mentions the fact in his journal as a remarkable circumstance, and his friend Anghiera, the secretary of Frdinand the Catholic, remarks with astonishment "that 'palmeta' and 'pineta' are found associated together in the newly-discovered land." It is a matter of much importance to geology to compare the present distribution of plants over the earth's surface with that exhibited in the fossil floras of the primitive world. The temperate zone of the southern hemisphere, which is so rich in seas and islands, and where p 283 tropical forms blend so remarkably with those of colder parts of the earth, presents according to Darwin's beautiful and animated descriptions,* the most instructive materials for the study of the present and the past geography of plants.

[footnote] *Charles Darwin, 'Journal of the Voyages of the Adventure and Beagle', 1839, p. 271.

The history of the primordial ages is, in the strict sense of the word, a part of the history of plants.

Cycadeae, which, from the number of their fossil species, must have occupied a far more important part in the extinct than in the present vegetable world, are associated with the nearly allied Coniferae from the coal formations upward. They are almost wholly absent in the epoch of the variegated sandstone which contains Coniferae of rare and luxuriant structure ('Voltizia, Haidingera, Albertia'); the Cycadeae, however, occur most frequently in the keuper and lias strata, in which more than twenty different forms appear. In the chalk, marine plants and naiades predominate. The forests of Cycadeae of the Jura formations had, therefore, long disappeared, and even in the more ancient tertiary formations they are quite subordinate to the Coniferae and palms.*

[footnote] *Goppert describes three other Cycadeae (species of Cycadites and Pterophyllum), found in the brown carboniferous schistose clay of Alt-sattel and Commotau, in Bohemia. They very probably belong to the Eocene Period. Goppert, 'Fossile Cycadeen', s. 61.

The lignites, or beds of brown coal* which are present in all divisions of the tertiary period, present, among the most ancient cryptogamic land plants, some few palms, many Coniferae having distinct annual rings, and foliaceous shrubs of a more or less tropical character.

[footnote] *['Medals of Creation', vol. i., ch. v., etc. 'Wonders of Geology', vol. i., p. 278, 392.] — Tr.

In the middle tertiary period we again find palms and Cycadeae fully established, and finally a great similarity with our existing flora, manifested in the sudden and abundant occurrence of our pines and firs, Cupuliferae, maples, and poplars. The dicotyledonous stems found in lignite are occasionally distinguished by colossal size and great age. In the trunk of a tree found at Bonn, Noggerath counted 792 annual rings.*

[footnote] *Buckland, 'Geology', p. 509.

In the north of France, at Yseux, near Abbeville, oaks have been discovered in the turf moors of the Somme which measured fourteen feet in diameter, a thickness which is very remarkable in the Old Continent and without the tropics. According to Goppert's excellent investigations, which, it is hoped, may soon be illustrated by plates, it would appear that "all the amber of the Baltic comes from p 284 a coniferous tree, which, to judge by the still extant remains of wood and the bark at different ages, approaches very nearly to our white and red pines, although forming a distinct species. The amber-tree of the ancient world ('Pinites succifer') abounded in resin to a degree far surpassing that manifested by any extant coniferous tree; for not only were large masses of amber deposited in and upon the bark, but also in the wood itself, following the course of the medullary rays, which, together with ligneous cells, are still discernible under the microscope, and peripherally between the rings, being some times both yellow and white."

"Among the vegetable forms inclosed in amber are male and femald blossoms of our native needle-wood trees and Cupuliferae, while fragments which are recognized as belonging to thuia, cupressus, ephedera, and castania vesca, blended with those of junipers and firs, indicate a vegetation different from that of the coasts and plains of the Baltic."*

[footnote] *{The forests of amber-pines, 'Pinites succifer', were in the southeastern part of what is now the bed of the Baltic, in about 55 degrees N. lat., and 37 degrees E. long. The different colors of amber are derived from local chemical admixture. The amber contains fragments of vegetable matter, and from these it has been ascertained tht the amber-pine forests contained four other species of pine (besides the 'Pinites succier'), several cypresses, yews, and junipers, with oaks, poplars, beeches, etc. — altogether forty-eight species of trees and shrubs, constituting a flora of North American chracter. There are also some ferns, mosses, fungi, and liverworts. See Professor Goppert, 'Geol. Trans.', 1845. Insects, spiders, small crustaceans, leaves, and fragments of vegetable tissue, are imbedded in some of the masses. Upward of 800 species of insects have been observed; most of them belong to species, and even genera, that appear to be distinct from any now known, but others are nearly related to indigenous species, and some are identical with existing forms, that inhabit more southern climes. — 'Wonders of Geology', vol. i., p. 242, etc.] — Tr.

We have now passed through the whole series of formations comprised in the geological portion of the present work, proceeding from the oldest erupted rock and the most ancient sedimentary formations to the alluvial land on which are scattered those large masses of rock, the causes of whose general distribution have been so long and variously discussed, and which are, in my opinion, to be ascribed rather to the penetration and violent outpouring of pent-up waters by the elevation of mountain chains than to the motion of floating blocks of ice.*

[footnote] *Leopold von Buch, in the 'Abhandl. der Akad. der Wissensch. zu Berlin', 1814-15, s. 161; and in Poggend., 'Annalen', bd. ix., s. 575; Elie de Beaumont, in the 'Annales des Sciences Naturelles', t. xix., p. 60.

The most ancient structures of the transition formation p 285 with which we are acquainted are slate and graywacke, which contain some remains of sea weeds from the silurian or cambrian sea. On what did these so-called 'most ancient' formations rest, if gneiss and mica schist must be regarded as changed sedimentary strata? Dare we hazard a conjecture on that which can not be an object of actual geognostic observation? According to an ancient Indian myth, the earth is borne up by an elephant, who in his turn is supported by a gigantic tortoise, in order that he may not fall; but it is not permitted to the credulous Brahmins to inquire on what the tortoise rests. We venture here upon a somewhat similar problem, and are prepared to meet with opposition in our endeavors to arrive at its soluion. In the first formation of the planets, as we stated in the astronomical portion of this work, it is probable that nebulous rings revolving round the sun were agglomerated into spheroids, and consolidated by a gradual condensation proceeding from the exterior toward the center. What we term the ancient silurian strata are thus only the upper portions of the solid crust of the earth. The erupted rocks which have broken through and upheaved these strata have been elevated from depths that are wholly inaccessible to our research; they must, therefore, have existed under the silurian strata, and been composed of the same association of minerals which we term granite, augite, and quartzose porphyry, when they are made known to us by eruption through the surface. Basing our inquiries on analogy, we may assume that the substances which fill up deep fissures and traverse the sedimentary strata are merely the ramifications of a lower deposit. The foci of active volcanoes are situated at enormous depths, and judging from the remarkable fragments which I have found in various parts of the earth incrusted in lava currents, I should deem it more than probable tht a primordial granite rock forms the substratum of the whole stratified edifice of fossil remains.*

[footnote] *See Elie de Beaumont, 'Descr. Geol. de la France', t. i., p. 65; Beaudant, 'Geologie', 1844, p. 269.

Basalt containing olivine first shows itself in the period of the chalk trachyte still later, while eruptions of granite belong, as we learn from the products of their metamorphic action to the epoch of the oldest sedimentary strata of the transition formation. Where knowledge can not be attained from immediate perceptive evidence, we may be allowed from induction, no less than from a careful comparison of facts, to hazard a conjecture by which granite would be restored p 286 to a portion of its contested right and title to be considered as a 'primordial' rock.

The recent progress of geognosy, that is to say, the more extended knowledge of the geognostic epochs characterized by differences of mineral formations, by the peculiarities and succession of the organisms contained within them, and by the position of the strata, whether uplifted or inclined horizontally, leads us, by means of the causal connection existing among all natural phenomena, to the distribution of solids and fluids into the continents and seas which constitute the upper crust of our planet. We here touch upon a point of contact between geological and geographical geognosy which would constitute the complete history of the form and extent of continents. The limitation of the solid by the fluid parts of the earth's surface and their mutual relations of area, have varied very considerably in the long series of geognostic epochs. They were very different, for instance, when carboniferous strata were horizontally deposited on the inclined beds of the mountain limestone and old red sandstone; when lias and oolite lay on a substratum of keuper and muschelkalk, and the chalk rested on the slopes of green sandstone and Jura limestone. If, with Elie de Beaumont, we term the waters in which the Jura limestone and chalk formed a soft deposit the 'Jurassic or oolitic', and the 'cretaceous seas', the outlines of these formations will indicate, for the two corresponding epochs, the boundaries between the already dried land and the ocean in which these rocks were forming. An ingenious attempt has been made to craw maps of this physical portion of primitive geography and we may consider such diagrams as more correct than those of the wanderings of Io or the Homeric geography, since the latter are merely graphic representations of mythical images, while the former are based upon positive facts deduced from the science of geology.

The results of the investigations made regarding the areal relations of the solid portions of our planet are as follows: in the most ancient times, during the silurian and devonian transition epochs, and in the secondary formations, including the trias, the continental portions of the earth were limited to insular groups covered with vegetation; these islands at a subsequent period became united, giving rise to numerous lakes and deeply-indented bays; and finally, when the chains of the Pyrenees, Apennines, and Carpathian Mountains were elevated about the period of the more ancient tertiary formations, large continents appeared, having almost their present p 287 size.*

[footnote] *[These movements, described in so few words, were doubtless going on for many thousands and tens of thousands of revolutions of our planet. They were accompanied, also, by vast but slow changes of other kinds. The expansive force employed in lifting up, by mighty movements, the northern portion of the continent of Asia, found partial vent; and from partial subsqueous fissures there were poured out the tabular masses of basalt occurring in Central India, while an extensive area of depression in the Indian Ocean, marked by the coral islands of the Laccadives, the Maldives, the great Chagos Bank, and some others, were in the course of depression by a counteracting movement. — Ansted's 'Ancient World', p. 346, etc.] — Tr.

In the silurian epoch, as well as in that in which the Cycadeae flourished in such abundance, and gigantic saurians were living, the dry land, from pole to pole, was probably less than it now is in the South Pacific and the Indian Ocean. We shall see, in a subsequent part of this work, how this preponderating quantity of water, combined with other causes, must have contributed to raise the temperature and induce a greater uniformity of climate. Here we would only remark in considering the gradual extension of the dry land, that, shortly before the 'disturbances' which at longer or shorter intervals caused the sudden destruction of so great a number of colossal vertebrata in the 'diluvial period', some parts of the present continental masses must have been completely separated from one another. There is a great similarity in South America and Australia between still living and extinct species of animals. In New Holland, fossil remains of the kangaroo have been found, and in New Zealand the semi-foxxilized bones of an enormous bird, resembling the ostrich, the dinornis of Owen,* which is nearly allied to the present spteryx, and but little so to the recently extinct dronte (dodo) of the island of Rodriguez.

[[footnote] *[See 'American Journal of Science', vol. xiv., p. 187; and 'Medals of Creation', vol. ii., p. 817; 'Trans. Zoolog. Society of London', vol. ii; 'Wonders of Geology', vol. i., p. 129.] — Tr.

The form of the continental portions of the earth may, perhaps, in a great measure, owe their elevation above the surrounding level of the water to the eruption of quartzose porphyry, which overthrew with violence the first great vegetation from which the matrial of our present coal measures was formed. The portions of the earth's surface which we term plains are nothing more than the broad summits of hills and mountains whose bases rest on the bottom of the ocean. Every plain is, therefore, when considered according to its submarine relations, an 'elevated plateau', whose inequalities have been covered over by horizontal deposition of new sedimentary formations and by the accumulation of alluvium.

p 288 Among the general subjects of contemplation appertaining to a work of this nature, a prominent place must be given, first, in the consideration of the 'quantity' of the land raised above the level of the sea, and next, to the individual configuration of each part, either in relation to horizontal extension (relations of form) or to vertical elevation (hypsometrical relations of mountain-chains). Our planet has two envelopes, of which one, which is general — the atmosphere — is composed of an elastic fluid, and the other — the sea — is only locally distributed, surrounding, and therefore modifying, the form of the land. These two envelopes of air and sea constitute a natural whole, on which depend the difference of climate on the earth's surface, according to the relative extension of the aqueous and solid parts, the form and aspect of the land, and the direction and elevation of mountain chains. A knowledge of the reciprocal action of air, sea, and land teaches us that great meteorological phenomena can not be comprehended when considered independently of geognostic relations. Meteorology, as well as the geography of plants and animals, has only begun to make actual progress since the mutual dependence of the phenomena to be investigated has been fully recognized. The word climate has certainly special reference to the character of the atmosphere, but this character is itself dependent on the perpetually concurrent influences of the ocean, which is universally and deeply agitated by currents having a totally opposite temperature, and of radiation from the dry land, which varies greatly in form, elevation, color, and fertility, whether we consider its bare, rocky portions, or those that are covered with arborescent or herbaceous vegetation.

In the present condition of the surface of our planet, the area of the solid is to that of the fluid parts as 1:2 4/5ths (according to Rigaud, as 100:270).*

[footnote] *See 'Transactions of the Cambridge Philosophical Society', vcl. vi., Part ii., 1837, p. 297. Other writers have given the ratio as 100:284.

The islands form scarcely 1/22d of the continental masses, which are so unequally divided that they consist of three times more land in the northern than in the southern hemisphere; the latter being, therefore, pre-eminently oceanic. From 40 degrees south latitude to the Antarctic pole the earth is almost entirely covered with water. The fluid element predominates in like manner between the eastern shores of the Old and the western shores of the New Continent, being only interspersed with some few insular groups. The learned hydrographer Fleurieu has very justly named this p 289 vast oceanic basis, which, under the tropics, extends over 145¼degrees of longitude, the 'Great Ocean', in contradistinction to all other seas. The southern and western hemispheres (reckoning the latter from the meridian of Teneriffe) are therefore more rich in water than in any other region of the whole earth.

These are the main points involved in the consideration of the relative quantity of land and sea, a relation which exercises so important an influence on the distribution of temperature, the variations in atmospheric pressure, the direction of the winds, and the quantity of moisture contained in the air, with which the development of vegetation is so essentially connected. When we consider that nearly three fourths of the upper surface of our planet are covered with water,* we shall be less surprised at the imperfect condition of meteorology before the beginning of the present century, since it is only during the subsequent period that numerous accurate observations on the temperature of the sea at different latitudes and at different seasons have been made and numerically compared together.

[footnote] *In the Middle Ages, the opinion prevailed that the sea covered one seventh of the surface of the globe, an opinion which Cardinal d'Ailly ('Imago Mundi', cap. 8) founded on the fourth apocryphal book of Esdras. Columbus, who derived a great portion of his cosmographical knowledge from the cardinal's work, was much interested in upholding this idea of the smallness of the sea, to which the misunderstood expression of "the ocean stream" contributed not a little. See Humboldt, 'Examen Critique de l'Hist. de la Geographie', t. i., p. 186.

The horizontal configuration of continents in their general relations of extension was already made a subject of intellectual contemplation by the ancient Greeks. Conjectures were advanced regarding the maximum of the extension from west to east, and Dicaearchus placed it, according to the testimony of Agathemerus, in the latitude of Rhodes, in the direction of a line passing from the Pillars of Hercules to Thine. This line, which has been termed 'the parallel of the diaphragm of Dicaearchus', is laid down with an astronomical accuracy of position, which, as I have stated in another work, is well worthy of exciting surprise and admiration.*

[footnote] *Agathemerus, in Hudson, 'Geographi Minores', t. ii., p. 4. See Humboldt, 'Asie Centr.', t. i., p. 120-125.

Strabo, who was probably influenced by Eratosthenes, appears to have been so firmly convinced that this parallel of 36 degrees was the maximum of the extension of the then existing world, that he supposed it had some intimate connection with the form of the earth, and therefore places under this line the continent whose existence p 290 he divined in the northern hemisphere, between Theria and the coasts of Thine.*

[footnote] *Strabo, lib. i., p. 65, Casaub. See Humboldt, 'Examen Crit.', t. i., p. 152.

As we have already remarked, one hemisphere of the earth (whether we divide the sphere through the equator or through the meridian of Teneriffe) has a much greater expansion of elevated land than the opposite one: these two vast ocean-girt tracts of land, which we term the eastern and western, or the Old and New Continents, present, however, conjointly with the most striking contrasts of configuration and position of their axes, some similarities of form, especially with reference to the mutual relations of their opposite coasts. In the eastern continent, the predominating direction — the position of the major axis — inclines from east to west (or, more correctly speaking, from southwest to northeast), while in the western continent it inclines from south to north (or, rather, from south-southeast to north-northwest). Both terminate to the north at a parallel coinciding nearly with that of 70¼degrees, while they extend to the south in pyramidal points, having submarine prolongations of islands and shoals. Such, for instance, are the Archipelago of Tierra del Fuego, the Lagullas Bank south of the Cape of Good Hope, and Van Diemen's Land, separated from New Holland by Bass's Straits. Northern Asia extends to the above parallel at Cape Taimura, which, according to Krusenstern, is 78 degrees 16', while it falls below it from the mouth of the Great Tschukotsehja River eastward to Behring's Straits, in the eastern extremity of Asia — Cook's East Cape — which, according to Beechey, is only 66 degrees E.*

[footnote] *On the mean latitude of the Northern Asiatic shores, and the true name of Cape Taimura (Cape Siewere-Wostotschnoi), and Cape Northeast (Schalagskoi Mys), see Humboldt, 'Asie Centrale', t. iii., p. 35, 37.

The northern shore of the New Continent follows with tolerable exactness the parallel of 70 degrees, since the lands to the north and south of Barrow's Strait, from Boothia Felix and Victoria Land, are merely detached islands.

The pyramidal configuration of all the southern extremities of continents belongs to the 'similtudines physicae in configuratione mundi', to which Bacon already called attention in his 'Novum Organon', and with which Reinhold Foster, one of Cook's companions in his second voyage of circumnavigation, connected some ingenious considerations. On looking eastward from the meridian of Teneriffe, we perceive that the southern extremities of the three continents, viz., Africa as the extreme p 291 of the Old World, Australia, and South America, successively approach nearer toward the south pole. New Zealand, whose length extends fully 12 degrees of latitude, forms an intermediate link between Australia and South America, likewise terminating in an island, New Leinster. It is also a remarkable circumstance that the greatest extension toward the south falls in the Old Continent, under the same meridian in which the extremest projection toward the north pole is manifested. This will be perceived on comparing the Cape of Good Hope and the Lagullas Bank with the North Cape of Europe, and the peninsula of Malacca with Cape Taimura in Siberia.*

[footnote] *Humboldt, 'Asie Centrale', t. i., p. 198-200. The southern point of America, and the Archipelago which we call Terra del Fuego, lie in the meridian of the northwestern part of Baffin's Bay, and of the great polar land, whose limits have not as yet been ascertained, and which, perhaps, belongs to West Greenland.

We know not whether the poles of the earth are surrounded by land or by a sea of ice. Toward the north pole the parallel of 82 degrees 55' has been reached, but toward the south pole only that of 78 degrees 10'.

The pyramidal terminations of the great continents are variously repeated on a smaller scale, not only in the Indian Ocean and in the peninsulas of Arabia, Hindostan, and Malacca, but also, as was remarked by Eratosthenes and Polybius, in the Mediterranean, where these writers had ingeniously compared together the forms of the Iberian, Italian, and Hellenic peninsulas.*

[footnote] *Strabo, lib. ii., p. 92, 108, Cassaub.

Europe, whose area is five times smaller than that of Asia, may almost be regarded as a multifariously articulated western peninsula of the more compact mass of the ontinent of Asia, the climatic relations of the former being to those of the latter as the peninsula of Brittany is to the rest of France.

[footnote] *Humboldt, 'Asie Centrale', t. iii., p. 25. As early as the year 1817, in my work 'De distributione Geographica Plantarum, secundum caels temperiem et altitudinem Montium', I directed attention to the important influence of compact and of deeply-articulated continents on climate and human civilization, "Regiones vel per sinus lunatos in longa cornua porrectae, angulois littorum recessibus quasi membratim discerptae, vel spatia patentia in immensum, quorum littora nullis incisa angulis ambit sine aufractu oceanus" (p. 81, 182). On the relations of the extent of coast to the area of a continent (considered in some degree as a measure of the accessibility of the interior), see the inquiries in Berghaus, 'Annalen der Erdkunde', bd. xii., 1835, s. 490, and 'Physikal. Atlas', 1839, No. iii., s. 69.

The influence exercised by the articulation and higher development of the form of a continent on the moral and intellectual condition of nations was remarked by Strabo,* who extols p 292 the varied form of our small continent as a special advantage.



[footnote] *Strabo, lib. ii., p. 92, 198. Casaub.

Africa* and South America, which manifest so great a resemblence in their configuration, are also the two continents that exhibit the simplest littoral outlines.

[footnote] *Of Africa, Pliny says (v. 1), "Nec alia pars terrarum paudiores recipit sinus." The small Indian peninsula on this side the Ganges present, in its triangular outline, a third analogous form. In ancient Greece there prevailed an opinion of the regular configuration of the dry land. There were four gulfs or bays, among which the Persian Gulf was placed in opposition to the Hyrcanian or Caspian Sea (Arrian, vii., 16; Plut., 'in vita Alexandri', cap. 44; Dionys. Perieg., v. 48 and 630, p. 11, 38, Bernh.). These four bays and the isthmuses were, according to the optical fancies of Agesianax, supposed to be reflected in the moon (Plut., 'de Facie in Orbem Lunae', p. 921, 19). Respecting the 'terra quadrifida', or four divisions of the dry land, of which two lay north and two south of the equator, see Macrobius, 'Comm. in Somnium Scipionis', ii., 9. I have submitted this portion of the geography of the ancients, regarding which great confusion prevails, to a new and careful examination, in my 'Examen Crit. de l'Hist. de la Geogr.', t. i., p. 119, 145, 180-185, as also in 'Asie Centr.', t. ii., p. 172-178.

It is only the eastern shores of Asia, which, broken as it were by the force of the currents of the ocean* ('fractas ex aequore terra'), exhibit a richly-variegated configuration, peninsulas and contiguous islands alternating from the equator to 60 degrees north latitude.

[footnote] *Fleurieu, in 'Voyage de Marchand autour du Monde', t. iv., p. 38-42.

Our Atlantic Ocean presents all the indications of a valley. It is as if a flow of eddying waters had been directed first toward the northeast, then toward the northwest, and back again to the northeast. The parallelism of the coasts north of 10 degrees south latitude, the projecting and receding angles, the convexity of Brazil opposite to the Gulf of Guinea, that of Africa under the same parallel, with the Gulf of the Antilles, all favor this apparently speculative view.*

[footnote] *Humboldt, in the 'Journal de Physique', liii., 1799, p. 33; and 'Rel. Hist.', t. ii., p. 19; t. iii., p. 189, 198.

In this Atlantic valley, as is almost every where the case in the configuration of large continental masses, coasts deeply indented, and rich in islands, are situated opposite to those possessing a different character. I long since drew attention to the geognostic importance of entering into a comparison of the western coast of Africa and of South America within the tropics. The deeply curved indentation of the African continent at Fernando Po, 4 degrees 30' north latitude, is repeated on the coast of the Pacific at 18 degrees 15' south latitude, between the Valley of Arica and the Morro de Juan Diaz, where the Peruvian coast suddenly changes the direction from wouth to north which it had previously followed, and inclines to the northwest. This change p 293 of direction extends in like manner to the chain of the Andes, which is divided into two parallel branches affecting not only the littoral portions,* but even the eastern Cordilleras.

[footnote] *Humboldt, in Poggendorf's 'Annalen der Physik', bd. xl., s. 171. On the remarkable fiord formation at the southeast end of America, see Darwin's Journal ('Narrative of the Voyages of the Adventure and Beagle', vol. iii.), 1839, p. 266. The parallelism of the two mountain chains is maintained from 5 degrees north latitude. The change in the direction of the coast at Arica appears to be in consequence of the altered course of the fissure, above which the Cordillera of the Andes has been upheaved.

In the latter, civilization had its earliest seat in the South American plateaux where the small Alpine lake of Titicaca bathes the feet of the colossal mountains of Sorata and Illimani. Further to the south, from Valdiva and Chilo‘ (40 degrees to 42 degrees south latitude), through the Archipelago 'de los Chonos' to 'Terra del Fuego', we find repeated that singular configuration of 'fiords' (a blending of narrow and deeply-indented bays), which in the Northern hemisphere characterizes the western shores of Norway and Scotland.

These are the most general considerations suggested by the study of the upper surface of our planet with reference to the form of continents, and their expansion in a horizontal direction. We have collected facts and brought forward some analogies of configuration in distant parts of the earth, but we do not venture to regard them as fixed laws of form. When the traveler on the declivity of an active volcano, as, for instance, of Vesuvius, examines the frequent partial elevations by which portions of the soil are often permanently upheaved several feet above their former level, either immediately precediing or during the continuance of an eruption, thus forming roof-like or flattened summits, he is taught how accidental conditions in the expression of the force of subterranean vapors, and in the resistance to be overcome, may modify the feeble perturbations in the equilibrium of the internal elastic forces of our planet may have inclined them more to its norther than to its southern direction, and caused the continent in the eastern part of the globe to present a broad mass, whose major axis is almost parallel with the equator, while in the western and more oceanic part the southern extremity is extremely narrow.

Very little can be empirically determined regarding the causal connection of the phenomena of the formation of continents, or of the analogies and contrasts presented by their p 294 configuration. All that we know regarding this subject resolves itself into this one point, that the active cause is subterranean; that continents did not arise at once in the form they now present, but were, as we have already observed, increased by degrees by means of numerous oscillatory elevations and depressions of the soil, or were formed by the fusion of separate smaller continental masses. Their present form is, therefore, the result of two causes, which have exercised a consecutive action the one on the other; the first is the expression of subterranean force, whose direction we term accidental, owing to our inability to defint it, from its removal from within the sphere of our comprehension, while the second is derived from forces acting on the surface, among which volcanic eruptions, the elevation of mountains, and currents of sea water play the principal parts. How totally different would be the condition of the temperature of the earth, and consequently, of the state of vegetation, husbandry, and human society, if the major axis of the New Continent had the same direction as that of the Old Continent; if, for instance, the Cordilleras, instead of having a southern direction, inclined from east to west; if there had been no radiating tropical continent, like Africa, to the south of Europe; and if the Mediterranean, which was once connected with the Caspian and Red Seas, and which has become so powerful a means of furthering the intercommunication of nations, had never existed, or if it had been elevated like the plains of Lombardy and Cyrene?