Geology and TopogTciphy of Western Neic York. 105 



tion than at present, and was on a level with this ancient beach, 

 and that, from some unexplained cause, it has subsided to its pres- 

 ent level and dimensions. 



I have long suspected some fallacy in this theory, and have 

 anxiously awaited the result of accurate levelings. It may be 

 deemed equally probable, and more consonant with the views 

 here suggested, to suppose, that, after the principal tides were shut 

 out from this inland sea, and the water had become nearly or 

 quite fresh, but while it was on a level, or nearly so, with the 

 Atlantic, the uphfting process became stationary, for an indefinite 

 period ; during which season of quiescence, this beach was thrown 

 up. At some subsequent time, the disturbing force again became 

 active, raising the basin of Lake Ontario, above the further influ- 

 ence of the ocean ; and fixing the present levels and boundaries 

 of this part of the continent. Should the statement of Mr. James 

 Hall prove well founded, and actual admeasurement confirm the 

 estimates of his assistant. Dr. George W. Boyd, this view of the 

 subject will be clearly established ; although these gentlemen do 

 not seem to have drawn such an inference. Mr. Hall states the 

 elevation of the ridge in Niagara county, at about 160 feet; and 

 admits variations in its level, of a few feet.* Dr. Boyd estimates 

 its elevation in Wayne county at more than 200 feet.f If this 

 diversity of level actually exists — as I have long suspected would 

 prove to be the case — it fixes the elevation at a period subsequent 

 to the formation of this beach. Its increased elevation, in ap- 

 proaching the primitive district, is what should be inferred, on 

 the theory, that those districts were the original centers of ele- 

 vation. And the variation of forty feet in about one hundred 

 miles, is quite as much as ought to be expected from an elevation 

 of but four hundred feet, which is the height of this ridge, or 

 ancient beach, in Niagara county, above tide water. 



* Second New York Geological Report, p. 310. - t Ibid. p. 312. 



Vol. XXXV.— No. 1. 14 



