196 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



of land when the sea-bottoms of these estuaries and shores were up- 

 raised, caused the extinction of these great quadrupeds. 



Although the great tract of country from the Baltic to the ele- 

 vated region westward of the Ural Mountains has not been locally- 

 broken up by eruptive rocks, there is ample evidence to prove that it 

 has been subjected to the action of subterranean forces, which ele- 

 vated the whole region, after the deposition of Miocene tertiary beds, 

 and after the land, while submarine, had assumed its present form. 

 " From the German Ocean and Hamburgh on the west to the White 

 Sea on the east, a vast zone of country, having a length of near 2000 

 miles, and a width varying from 400 to 800 miles, is more or less 

 covered with loose detritus, including erratic crystalline blocks of 

 colossal size, the whole of which blocks have been derived from the 

 Scandinavian chain." The eastern and south-eastern boundary of 

 these erratic blocks mark the line of coast westward of which all the 

 land as far as the shores of the Baltic was then submerged. Between 

 that line of coast and the Urals is the region that constitutes the 

 Governments of Perm, Viatka and Orenburg ; and for a consider- 

 able space to the west of the Ural there is not a vestige of any super- 

 ficial deposit which can be referred to the influence of the sea. " We 

 believe, therefore," say the authors, " that the region so characterized 

 was really above the waters, and inhabited by mammoths, when the 

 erratic blocks were transported over the adjacent north-western sea." 

 The amount of this elevation, subsequent to the covering of the sea- 

 bottom by the northern drift, must have been at least from 800 to 

 1000 feet; for the tops of the Valdai hills, a range on the eastern 

 borders of Lithuania, and to the south of the Government of St. 

 Petersburg, which rise in some places to that height, are covered 

 with these blocks on their southern slopes. 



Mr. Lyell, speaking of the country near Savannah in North Ame- 

 rica, says, " It is evident that at a comparatively recent period, since 

 the Atlantic was inhabited by the existing species of marine tes- 

 tacea, there was an upheaval and laying dry of the bed of the ocean 

 in this region. The flat country of marshes was bounded on its 

 inland side by a steep bank or ancient cliff", cut in the sandy tertiary 

 strata ; and there are other inland cliffs of the same kind, at different 

 heights, implying the successive elevation above the sea of the whole 

 tertiary region." In a letter which I received from him a few days 

 ago, dated from Savannah, Mr. Lyell tells me " that he had seen on 

 the coast of Georgia quite a counterpart of the terraces, or successive 

 cliffs of Patagonia, cut out of the tertiary deposits." But there are 

 also evidences on that coast of a downward movement at the present 

 time. Mr. Lyell says, "There have also been subsidences on the 

 coast, and perhaps far inland ; for in many places near the sea there 

 are signs of a forest having become submerged, the remains of erect 

 trees being seen enveloped in stratified sand and mud. I even sus- 

 pect that this coast is now sinking down at a slow and insensible 

 rate, for the sea is encroaching and gaining at many parts on the 

 freshwater marshes. . . .Everywhere there are proofs of the coast ha- 

 ving sunk, and the subsidence seems to have gone on in very modern 



