310 Horner's Geological Address. 



species of marine testacea, there was an upheaval and lay- 

 ing 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 cliif, 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 w^hole 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 deposites." 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 suspect 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 having sunk, and the subsidence seems 

 to have gone on in very modern times." Speaking of some 

 phenomena connected with a boulder formation at Brooklyn 

 near New York, he says that he had come to the conclusion, 

 " that the drift was deposited during the successive sub- 

 mergence of a region which had previously been elevated and 

 denuded, and which had already acquired its present leading 

 geographical features and superficial configuration." In the 

 region near the Falls of Niagara, on Lake Ontario, and in 

 the valley of the St Lawrence, he enumerates many unequi- 

 vocal proofs of emergence and submergence during the mo- 

 dern period now under consideration. He states, that in the 

 valley of the St Lawrence he seemed to have got back to Nor- 

 way and Sweden, passing over enormous spaces covered by 

 deposites so modern as to contain exclusively shells of recent 

 species, resting on the oldest palaeozoic and older non-fossi- 

 liferous rocks. Wide areas are covered with marine shells of 

 recent species, at the height of 500 feet above the sea, and 

 where all the rocks can be shewn both to have sunk and to 

 have been again uplifted bodily, for a height and depth of 



