The products of these tertiary extinct volcanoes are indeed vastly inferior in amount to the ejections of the more ancient periods, whose stupendous monuments are seen in the primary and secondary mountain-chains of granite, porphyry, and greenstone; but still they had force enough to influence very extensive tracts of country, to convulse and move large portions of the crust of the earth. Even now it is impossible to guess through how wide an extent, in the subterranean regions, the shock of earthquakes is simultaneously felt. Not less than 100,000 square miles of country were permanently elevated by the Chili earthquake of 1822, from two to six feet above its former level, and part of the bottom of the sea remained dry at high water, with beds of oysters, muscles, and other shells adhering to the rocks on which they grew. The contemplation of volcanic phenomena in South America, has led Mr. Darwin to remark that, in order to comprehend the vast surface which was affected by the earthquake in Chili, and which destroyed Conception, in February 1835, it had a north and south range equal in extent to the distance between the North Sea and the Mediterranean—that we must imagine the eastern coast of England to be permanently raised, and a train of volcanoes to become active in the southern extremity of Norway—also that a submarine volcano burst forth near the northern extremity of Ireland—and that the long dormant volcanoes of the Cantal and Auvergne, each sent up a column of smoke. It need, therefore, excite no wonder that geologists have felt themselves warranted to ascribe the elevation not only of the sedimentary formations in central France to the volcanic movements of the district, but likewise those of the Paris and London basins, as well as the general rise and dislocation of the strata along the southern and eastern coasts of England. The cause, as compared with recent and still daily observed phenomena, was abundantly adequate to effect the results. Other districts would be simultaneously influenced; the tertiary deposits in their various successive groups were all arranged under similar circumstances and exposed to similar changes; and hence a doubt can scarcely exist, that all these geological basins, and this vast superficies of tertiary matter, were cotemporaneously elevated, as well as subjected to one and the same range of subterranean convulsion.