English Formations.

Formations of the Continent.

1. London and Hampshire Ba- 1. Basin of Paris; Valleys of the

sins, Lignites, and Glance

coal. Imperfect wood coal.

Alum Bay, Isle of Wight.

Po, Switzerland, the Danube. Lignites, and Glance coal. Perfect, and used for fires. Monte Bolca, and Arzignan in the Vicentino, Fussen in Bavaria.

Corfe clay pits. Isle of Pur- Titmoning, Teisendorf, Miesbach, beck.

and all the coal pits in the

valley of the Danube, above Vienna.

Marburg in Styria.

Leoben in Styria.

2. Puddingstone of Hertfordshire. 2. Nagelflue of Switzerland,

Druid sandstone blocks of Buckinghamshire, Wilts, and Dor

set.

3. Plastic clay formation. Clay, marl, sand, and gravel,

with marine shells.

Como, and Salzburg. Puddingstone of Rigi near Lu

cerne, and of Bregentz on Lake Constance.

3. Plastic clay formation. Beds of clay, marl, sand, and gravel, with marine shells.

Basins of London, Hants, and Basin of Paris.

With plants and marine fish. With plants and marine fish.

Isle of Sheppy.

Monte Bolca, near Verona.

Solenhofen, near Pappenheim

The mountain limestone and great coal formations of England do not occur in the Alps. The tertiary formations which constitute the molasse and nagelflue of the Great Valley of Switzerland, have

been mistaken for the new red sandstone beds of England. These mistakes proceed partly from the enlarged bulk, and partly from the want of distinct features, and of tangible character, which accompany all secondary strata as they enter the Alps. But their identity with the English formations has been evinced by actual sections. It has been shown that a constant and regular order of succession prevails in the alpine and transalpine districts, and generally over the Continent; and that this order is the same that exists in our own country. It is remarkable that our oolite and magnesian limestones (under the name of alpine limestones) rise into the most elevated crests and pinnacles, that crown the summits of this gigantic chain. The following are among the greatest heights which they reach :

In the Pyrenees also, the same limestones form the most elevated ridge, and great water shed of that vast chain; rising in Mount Perdu to 10,578 feet, and in the Torre de Marbore to 10,260,

CHAP. II.-SUBMEDIAL STRATA.

1. GREYWACKE is commonly composed of grains or fragments of quartz, and lydian stone, among which bits of clay-slate are disseminated. These parts are agglutinated by a cement of an argillaceous

GREYWACKE FORMATION.

141

kind, usually impregnated with coarse siliceous matter. The size of the grains of quartz and lydian stone, rarely exceeds a nut; but the pieces of clayslate are sometimes as large as the hand. Occasionally these fragments are so comminuted, as to be no longer discernible; the rock takes then a schistose texture approaching to clay-slate.

But the main body of the submedial rocks is composed of clay-slate itself, containing certain subordinate beds, such as masses of talc, &c. The clay slates of Glaris, in Switzerland, celebrated for their casts of fishes, are accompanied with talcose rocks. Here also, we find alum-slate, which is merely an argillaceous schist, impregnated with carbon and sulphur; the latter probably in the state of sulphuret of iron. The transition clay-slate of Sweden and Norway, is so rich in these beds, as to be worked for them alone. When exposed to the air, they get covered with a snowy efflorescence, just as happens to some of the argillaceous slates of our coal measures. This was finely exemplified in the waste coal workings that form the Hurlet Alum mines, near Glasgow. The carbon occasionally accumulates to such a degree in some portions of the slate, as to form masses of stone coal (anthracite,) a substance which burns with difficulty, and can be made use of merely for calcining limestone. The surrounding slate affords vegetable impressions of reeds and analogous plants. The animal exuviæ are not numerous in these transition strata. They consist of madrepores, trilobites, ammonites, and terebratulites, casts of turbinites and striated camites. But certainly the most characteristic feature

of this submedial formation, is the impressions of fish, indicating most clearly the dreadful turmoil which presided at its origin.

Fish which perish by a natural death, necessarily become the food of other fish like themselves, or of crustacea. We need not therefore be surprised, at finding none of their remains, in situations which abound with them in the living state. It is not

Bolca, and other localities; where a volcanic eruption, or some other sudden revolution had killed them all at once. In certain places their remains occur, lying on their belly, or lengthwise, with their fins and tail extended. These remains, in some cases, consist of bones, spines, and scales, distributed in their natural positions, In others, they are found in a constrained posture, suggesting the idea, that they had perished in boiling water; examples of which, have occurred in the sub-marine volcanoes of modern times. Lastly, in certain localities, as at Plattenberg, in the canton of Glaris, they are in a flattened state, and covered with scales, but destitute of bony skeleton.

It cannot be doubted that the revolution which caused the vast accumulation of remains found at Monte-Bolca, must have been sudden, and that they were speedily covered after death, by the mineral deposit in which they are now buried; for one of