THE HIGH TERIIACE IN AMHERST. 



647 



shore line I liave at one time or anotlier had opj)ortuiiity, in cnttings of tlie 

 water or gas companies, to locate exactly this old shore line and plain. 



College Hill breaks down like Mount Pleasant, and southwest, at Professor 

 Harris's house, begins another drundin, named Mount Donia (l)y President 

 Hitchcock), from its regular shape. Between the two the waters passed 

 southeast into the depression south of College Hill, and a broad, thin sheet 

 of gravel stretches through the pass, and is well exposed in the cutting of 

 the Central Railroad. Everywhere through this jjass the till is but a little 

 distance — at iiiost 6 feet — below the surface, as at the bridge over this 

 cuttinof on Woodside avenue. 



Fig. 38.— Enlarged 



Fig. 37 shows a section south from the Octagon, on College Hill, through 

 the cutting of the Central Railroad, at the point where the highway crosses 

 it. It is interesting as showing sands under the clays and separating them 

 from the till. This is the ouly instance of the kind I huxe seen in the 

 valley. The clays thicken off into the deep water south and southeast, and 

 northward grade to sand layers, and these to the beach gravels which make 

 this broad flat and which are si)read over the bench cut back in the till, by 

 which cutting the sharp slope south of the Octagon was produced. The 

 varying cun-ents from the west are finely shown by the detailed sections 

 figs. 38, 39. The quiet water allowed the clay layers to form, and then the 

 strong current crumpled them. 



