THE REIGN OF ICE. 217 



storm, or flood. But its lowering brow shows the deep 

 scars of many a fierce conflict. The attacks have evident- 

 ly proceeded from the north. On this side the perpendic- 

 ular walls are smoothed and scored in precisely the same 

 manner as the dome-shaped mass to which I have just al- 

 luded. The southern side retains, like the other mass, 

 many of the angularities produced by the original fractures 

 of the formation. Similar features are things of e very-day 

 observation, but people never suspect what mighty and 

 what extraordinary agencies have been employed in pro- 

 ducing them. All our low rocky hills and bluffs are sim- 

 ilarly pared off upon their summits and northern exposures, 

 while their southern aspects are more rugged. The great 

 glacier has passed over them, striking them from the north, 

 and grinding down their northerly projections and angu- 

 larities. These phenomena have been especially studied 

 and illustrated in New England by the lamented Dr. Hitch- 

 cock. On the western end of Lake Erie, at Stony Point, 

 the surface of the Corniferous limestone lies two or three 

 feet above the level of the water. Upon this have been 

 deposited four or five feet of gravel and soil. On the im- 

 mediate shore ; the storm- waves have easily washed off the 

 overlying beds, and left acres of the limestone completely 

 exposed to view. What do we find to be the character of 

 this original surface ? Level and smooth as a floor — 

 planed down by the energy of the omnipresent glacier — 

 but marked, besides, by some deep furrows, which extend 

 from edge to edge of the uncovered table in lines as 

 straight and strictly parallel as if marked by the " gauge" 

 of some Titanic stone-worker. One set of the furrows, in 

 particular, arrests the attention, since the visitor can not 

 fail to recognize their resemblance to the deep ruts pro- 

 duced by a loaded wagon moving over a soft and clayey 

 surface (Fig. 81). 



K 



