Essay on the Theory of the Earth

by baron Georges Cuvier

The formations anterior to the chalk, and in the hollows of which the chalk is itself deposited, as the formations of our neighbourhood are in its hollows, form a great part of Germany and England; and the efforts which the naturalists of these two countries have recently made according with ours, and proceeding upon the same principles, combined with those which had been previously tried by the school of Werner, will soon leave nothing to be desired with respect to our knowledge of them. Messrs de Humboldt and de Bonnard in France and Germany, and Messrs Buckland and Conybeare in England, have furnished the most complete and most instructive accounts of them.

The subjoined table, in which not only the secondary formations have been arranged, but the whole series of strata, from the oldest known to the most modern and most superficial, has been politely furnished me by M. de Humboldt, to adorn my work. It may be considered as an epitome of the labours of geologists up to the present period[246].

TABLE of Geological Formations in the order of their superposition. By M. Al. de Humboldt.

Alluvial Deposits.			Tertiary Formations.
Lacustrine Formation with Buhrstones.
Fountainbleau sandstone and sand.
Gypsum with bones. Siliceous Limestone.
Coarse Limestone. (London Clay.)
Tertiary sandstone with lignites.
(Plastic clay,—Molasse,—Nagelfluhe.)
Chalk.	white. tufaceous. chloritic.	Ananchites.
Green sand. Weald clay. Iron Sand.	(Secondary Sandstone with lignites.)		Secondary Formations.
Ammonites. Planulites.	Jura Limestone.	Slaty beds with fishes and crustacea.
Quadersandstein, or white sandstone, sometimes above the lias.		Coral rag. Dive clay. Oolites and Caen limestone.
Muschelkalk. Ammonites nodosus.		Marly or calcareous lias with Gryphæa arcuata.
Marls with fibrous gypsum. Arenaceous beds.		Saliferous variegated sandstone.
Productus aculeatus. Magnesian limestone.	Zechstein. Copper slate.	(Alpine limestone.)
Quartziferous Porphyry.	Co-ordinate formations of porphyry, red sandstone, and coal.
Transition Formations.
Slates with Lydian-stone, greywacke, diorites, euphotides. Limestones with orthoceratis, trilobites and euomphalites.
Primitive Formations.
Clayslates (Thonschiefer). Micaslates. Gneiss. Granites.

Under the chalk are found deposits of green sand, of which its lower strata contains some organic remains. Beneath this are ferruginous sands. In many countries both of these deposits are agglutinated into beds of sandstone, in which lignites, amber, and remains of reptiles, are also observed.

Under this, we find the great mass of strata which compose the Jura chain, and that of the mountains by which it is continued into Suabia and Franconia, the principal ridges of the Apennines, and multitudes of beds in France and England. It consists of limestone-schists, rich in fishes and crustacea; vast beds of oolites, or of a granular limestone; grey marly limestones, with pyrites, characterised by the presence of ammonites, of oysters with recurvate valves, named Gryphææ, and of reptiles, which are remarkable on account of their forms and structures.

Large beds of sand and sandstone, often presenting vegetable impressions, support all these Jura deposits, and are themselves supported by a limestone, the innumerable shells and zoophytes contained in which induced Werner to give it the much too general name of Shell-limestone, and which is separated by other beds of sandstone, of the kind denominated variegated sandstone, from a still older limestone, which has been not less improperly called Alpine limestone, because it composes the High Alps of the Tyrol; but which also shews itself at the surface in the eastern provinces of France, and in the whole southern part of Germany.