[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, 'Oss.e.m.e.ns 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 Goniat.i.tes, Trilobites, or Nummulites, sometimes const.i.tutes 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 a.s.sociation 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 quant.i.ty of Ammonites into well-characterized families, and to show that Cerat.i.tes appertain to the muschelkalk, Arietes to the lias, and Goniat.i.tes 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 sh.e.l.l-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 Jura.s.sic 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 ident.i.ty 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 cla.s.sify 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, const.i.tute his 'palaeozoic formatiions'. According to these views, the chalk and Jura const.i.tute 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 cla.s.sification 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, 'Oss.e.m.e.ns 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 pa.s.sed 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 a.n.a.lysis 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 (gra.s.ses, 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.