Page:A Treatise on Geology, volume 2.djvu/317

 CHAP. X.

Carboniferous period, of ordinary action; the sea filled with new sediments by inundations from the land which had been lately and previously uplifted. The series of organic remains undergoes an entire and apparently sudden change of species.

Another interval of dislocations, so general and remarkable, that there is not a coal field in Europe which appears to have been exempt from them. The geological date is not always assignable, except within the limits of the uppermost coal deposits, and the base of the new red sandstone. The whole period of rotheliegende and magnesian limestones may be included in this interval, and some of the peculiarities of the saliferous system are probably the effects of this great disturbance.

The oolitic and cretaceous periods appear to have been scarcely broken by any violence in the region of the British isles, but the whole bed of the sea underwent a gradual and continual rise, which brought up progressively the north-western parts of the oolitic rocks. (On the continent of Europe the oolitic and cretaceous periods were divided by an interval of great disturbance.)

An interval of extensive dislocations has been recognised by M. de Beaumont and others, under the title of the Pyreneo-Apennine system; in England the effects of disturbance are chiefly exemplified in the conglomerates and pebbles which abound in the lower tertiary strata.

The eocene period of Mr. Lyell succeeds, with a prodigious number of organic forms, almost wholly distinct from those of the older strata.

The dislocations of the western and eastern Alps, combined with the evidence afforded by diluvial phenomena and raised sea breaches in many parts of the world, appear to show a separation between the eocene and modern periods by a period of violent disturbances, connected with the rising of some of the highest mountain ranges in the world. The conjecture of De Beaumont, that the elevation of the Andes was one of the latest of these great disturbances, has been verified by