243 Notes oti American Geology. 



have been termed, to sand and pebbles which moving bodies of 

 ice carried in their resistless course. In the same manner I would 

 account for the polished surface of the rocks in Western New 

 York. Running water, carrying sand, gravel, pebbles and boul- 

 ders, to which cause this smooth appearance has been generally 

 attributed, would not be likely to polish the surfaces of rocks; 

 and moreover, where are those circular cavities, hollowed out by 

 whirlpools, the invariable record of bodies of water moving with 

 the velocity attributed to diluvial floods ? I doubt whether any 

 can be found on the polished surfaces of the rocks of the Alpine 

 regions, or on the vast horizontal floors of Western New York. 

 I never observed them in any place where evidence of "ancient 

 water-falls or rapids was not perfectly conclusive ; and they are 

 confined to valleys and the banks of existing streams. The 

 scratches and grooves, Mr. Hall informs us, on the rocks border- 

 ing the Genesee river, have a direction N. N. E, and S. S. W., 

 and they therefore probably follow the dip of the stratum, down 

 which the ice moved. Nothing is more certain, than that the 

 surface of the earth has risen unequally, or that two distant points 

 have been uplifted at the same period, one rising to a greater 

 height than the other, while the intermediate space was either 

 stationary or depressed. If a glacier had previously occupied this 

 area, the uphfts would have produced a synclinal line in the ice, 

 and pebbles and boulders thus brought from opposite directions^ 

 Mr. Hall has noticed this phenomenon, but attributes it to the 

 agency of opposing currents. He observes, " the presence, in 

 the same locality, of boulders from the north with those from the 

 south, proves that opposite forces have prevailed either at the 

 same or at different periods."* 



While granite boulders have been removed to surprising dis- 

 tances from the rocks in situ, those of transition limestone and 

 sandstone seem never to have been far removed from the parent 

 mass, a fact which harmonizes with the theory of refrigeration. 

 The vast thickness of granite, and its corresponding uplift from 

 the force of crystallization, has protruded its naked summits 

 through the overlying strata, and from these peaks, rising to a 

 great altitude, replete with parallel fissures, and split and rent by 

 the upheaving power, large masses would necessarily fall, and 



* Geological Reports, 1338, p. 308. 



