shells are imbedded. No volcanic specimens have ever yet been discovered in North Wales, where Llyn Peris lies; but detached places bear striking evidence of fluidical power. The hills of quartz, on the Congo, also, exhibit similar appearances.

Shells have often been discovered in English claypits. Among which are the concha anomiæ; and the nautilus græcorum;-materialy altered from their original state, by being impregnated with stone and clayish particles: near Wakefield, in alluvial soil, shapes of muscle shells in a fossil state, lying in a stratum of block limestone. The marbles and limestone in the neighbourhood of the caves in Yorkshire are described, as being made up of testaceous and piscaceous relics: and some have even supposed that all the chalks, marbles, gypsums, and limestone of this kingdom are formed of marine shells and animals :-An extravagance scarcely to be credited: yet Hutton' extends the idea even to the supposition, that the earth is, in a great measure, composed of the exuvia of marine animals. Dr. Fisher, on the other hand, believes that shells, thus discovered, are real stones : and the plants stone plants, formed after the manner of figured stones. And Misson inclines to the probability, that those shells never contained animals; but were generated, where they now are, in the same manner that chalks and other substances are:-a position contradicted by all the rules of analogy and experience; as well as by the certainty, that the veins of coal, called

Winch's Letter to the London Geological Society.

coal pipes, were originally small branches of trees. Indeed a large tree with its branches has lately been dug up, with its leaves, in a bed of fire-stone at High Heworth, near Newcastle.-Its trunk and larger branches were siliceous; but its leaves and twigs had been converted into coal. At Ardrossan, in Scotland, a tree was also discovered, by the blowing up of a rock; changed into an appearance of white stone. Even the colour of its bark and branches were dis tinguishable.

2

Coal-pits and slate quarries frequently exhibit impressions of vegetable substances. Even the trap rocks of Sweden are evidently of aqueous formation; impressions of ferns and fishes having been discover→ ed in them. On the Ohio' are found leaves, insects, and marine shells mixed in limestone'; in the caves of Green Briar,3in Virginia, the bones of the megalonyx; and in the alluvial soil of Teneriffe* clayey calcareous tufa, containing similar imprints. Trunks of palmtrees have even been thrown out of volcanoes :-and in the fissure of a lead-mine at Pontpian, near Rennes, a beech was discovered among a few sea-shells; the centre of which had been converted ito coal ;the bark into pyrites; and its sap-wood into jet.

1 Palmer's Travels, p. 67.

6

2 A superb specimen of zoophyte, three feet long and two feet wide, was lately discovered in blue lias formation, at Lyme Regis in Dorsetshire. 3 Americ. Transact. No. xxx.

4 Humboldt's Voy. Equinoct. vol. i. p. 237.

5 Mém. of M. de Fleurian, Humbold, Voy. Equin. vol. i.

6 Journal de Physique, Mai, 736.

p.

238.

V.

In Touraine,' there are 130,680,000 cubical fathoms of shells, unmixed with either stone, sand, or other extraneous matter, thirty-six leagues from the sea.The farmers manure their land with them. The environs of Paris afford, too, many striking phenomena. There bones of unknown animals occupy whole districts near which lie remains of animals, now natives of other climates. Vast collections of marine exuviæ have been discovered, in the very neighbourhood of which shells of fresh water fish are deeply imbedded. Let us examine the manner, in which these phenomena bear reference to each other.

2

I. The first formation is that of chalk, in which are unconnected flin's disposed in beds. There are also organic remains, of which twenty-two species have been described by Cuvier and Brogniart. II. This stratum of chalk is covered with a bed of plastic clay, containing no calcareous, but some siliceous matter. It is, in some places, seventeen yards thick; in others not above three inches. III. The stratum in succession is that of coarse limestone:-sometimes separated from the clay by a bed of sand. In this formation have been found six hundred species of fossils. These have been described by De France and De la Mark. IV. The fourth stratum consists of siliceous limestone, lying parallel with the above: but no or

Buffon. vol. i. p. 222.

⚫ Essai sur la Géographie Minéralogique des Environs de Paris. 1811.

4to.

ganic substance whatever has been discovered in it. V. Lying upon the siliceous limestone is a formation of alternate beds of gypsum, and of calcareous and argillaceous marls. In which have been discovered scattered bones, and entire skeletons of unknown birds and quadrupeds; and a few shells, evidently of a fresh water kind.

A little above these remains have also been found the bones of a tortoise, and of a crocodile; of a Parisian opossum ; a fine species of paleotherium'; five of anoplotherium2; a species of hog, and of a Parisian dog; a few fishes, and four unknown species of birds.

VI. The sixth formation is of marl; in which have have been discovered not only the remains of shells and fishes, but of a palm-tree. And immediately above these, in marl of marine origin, twenty-six species of fossil remains. VII. The seventh stratum consists of sand and sandstone without shells: over which is found-VIII. Sandstone, containing objects of marine formation; sixteen3 of which have been de

scribed by French geologists. IX. Is that of Buhr, used for millstones. X. Consists of marl and millstones,' in which are found shells, belonging to rivers and lakes ; with twenty species of seeds, reeds, siliceous wood, and other vegetable substances. XI. The eleventh formation is a stratum of what is technically called " travelled earth;" consisting of marl, rounded pebbles, pudding-stone, clay, sand, gravel, and peat moss. In these substances were trunks of trees, and the bones of oxen, rein-deer, elephants, and other large mammalia.2

It is interesting to remark, that part of this formation* (fresh-water) extends not only into the departments of Cher, Allier, Nievre, Cantal, Puy de Dome, Tarn, Lot, and the Garonne, but the same has been recently found in the Roman States, and in Tuscany; in the vicinities of Ulm, Mayence, and Silesia ;-and in several districts in Spain.

2 Webster has lately observed a series of rocks of the same general natúre, resting on the chalk formation in the south of England: for a minute account of which the reader is referred to the Geological Transactions. The succeeding list of organic remains will sufficiently confirm the propriety of the inferences, which may be drawn from the existence and dispositions of organic with geological substances.

Organic Remains in the lower Marine Formation above the Chalk in England.