THE TILL. • 543 



hills of drift are separated to the depth of the present l)ed of Mill River, 

 as is shown by the height of the l)Owlder clay in the section at the hoe 

 factory, already described. West of the asylum Sunset Hill and the long 

 wooded hills between which runs the road to Loudville form the most 

 elevated and extensive accumulation of drift in the valle^•. The first of 

 these hills, starting from the northwest corner of the asylum giounds, runs 

 southwesterly and is continued across the Loudville road by the higher and 

 more massive hill which is conspicuous at a distance fi'om the number of 

 great bowlders of whitened quartz-diorite (tonalite) that cover the broad 

 l)euches on its southeastern side. The road to Easthampton skirts this 

 hill for a long distance on its southern side, and the sands of the high 

 terrace abut upon its other slopes. 



This completes the chain of ridges, and a glance at the map will show 

 how they are swung in a broad curve, from J]lizabeth Rock to the West- 

 hampton Hills, across the mouth of the deep bay formed In- the recession 

 of the crystalline rocks. Within this bay two other prominent drumlins 

 take the same west-of-south direction — the wooded hill east of Florence 

 and the long steep elevation above Bay State on the north. And finally, 

 all the broad wooded area west of Mill River opposite Bay State is a con- 

 tinuous undulating area of bowlder clay, and from a point below Florence 

 nearly all the way to the asylum Mill River is wearing into it, and its 

 western bank is covered with abundant bowldei's from which the stream 

 has washed out the finer material, and here ai'e the best permanent sections 

 in the bowlder clay to be found in the vallev. 



Farther south, across Southampton and Westfield, the Champlain 

 sands occupy the greater portion of the valley bottom, and where the till 

 appears it is usually with an undulating surface and is made up of rather 

 fine-grained, reddish material, derived mainly from the red sandstone, very 

 compact, with bowlders nearly all under 1 foot in greatest length, and 

 thus is very different from the upland till. This is notably the case in all 

 the west half of Southwick. 



DRUMLINS. 



Perhaps the most notable contribution to science made by the Second 

 Geological Survey of New Hampshire was the recognition of this interesting 

 and peculiar form of drift hills, coupled as it was with a careful mapping of 

 their distribution and a satisfactory explanation of their origin. 



