242 Notes on 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? - 1 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 ‘anaaros: The 
scratches and grooves, Mr. Hall informs us,-on the rocks border- 
ing the Genesee river, have a direction N. N. E. and 8. 8. 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 uplifts 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 
locality, of boulders from the north with those from the 
south, proves that opposite forces have eae 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 iad 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 
great altitude, replete with parallel fissures, and split and rent by 
the upheaving power, large masses would necessarily fall, © 
= * Geolggical Reports, 1838, p. 308. 
