Page:A Treatise on Geology, volume 1.djvu/74

 58 of the great masses are the same: most of the systems of strata are also to be recognised, either in the mountains or the lower ground; and fresh additions to these analogies are continually added by geological travellers. But when we come to consider the constituent formations, discordance is manifested of the same kind as that which, as before observed, appears between different parts of England with respect to certain oolitic and carboniferous formations.

In Scandinavia, as well as along the Alps, and Grampians, hypozoic strata are predominant, while mica schist and gneiss are rare in the Harz, Cornwall, and Wales. There is more carboniferous limestone in England and Ireland than in all Europe besides. The oolites of Germany and France sometimes perfectly resemble, in composition and succession, that group in England; but on the Italian side of the Alps, and in Greece, they have different characters. The chalk formation is little seen about or beyond the Alps; and in the Carpathians green sand appears in plenty, but little or no chalk. Turning to more distant localities, we find, in North America, a vast series of widely spread stratified deposits, much allied to those of Europe, grouped, for the most part, in similar systems; but the series between the cretaceous and carboniferous rocks is much less developed than in Europe. On the contrary, in the Himalaya mountains, and the basin of the Indus, these formations are greatly developed, and rocks of the lias and oolitic formations are perfectly identified. As a general result, it appears already ascertained that the same great divisions of strata may be applied to nearly all parts of the globe; that, even in very distant localities, the same systems of strata were produced, though sometimes in isolated patches; but that the particular formations, though often very extensively spread, are yet somewhat irregular in their expansion, some extending in one direction, and others in a different one, so as clearly to evince their dependence on local and variable conditions.