INTERGLACIAL SANDS. 553 



bowlders G inches in g-reatest diaineter, whicli ciin he explained only as 

 above indicated. They are now ijockets of a niucli flattened ellipsoidMl 

 form, filled witii a liuff sand like that forming the layer below. 



This sand stratum was again finely exposed in the water-main ditch on 

 Amity street (a few rods north), on a line rmming east and west, and tlius 

 with the dip of the lamina' of the sands It rested, as before, upon the 

 irregular surface of the till below, and was covered here and there by frag- 

 ments of the second till, partly removed in grading the road. Thc^ santls 

 were exposed for a distance of 350 feet, commencing at a point opposite 

 the northwest corner of the cellar. Here they began as a thin, gravelly 

 bed, and, the till beneath dipping westward, they soon rcaclied ji thi(."kness 

 of more than (3 feet, and their whole depth was not exposed for GO feet. 

 Then the till rose nearly to the surface for 60 feet, and for the rest of tlie 

 distance the till appeared only here and there in low hummocks in the 

 bottom of the ditch, until at last the sands ran out to the surface on the 

 slope of the hill between the first and second layers of the till, opposite 

 Professor Crowell's house. 



The sands agreed in all jjarticulars with those already described in the 

 cellar section, presenting the same gradation from a fine, whitish, clayey 

 sand through buff sands to fine gravel, the same flow-and-plunge structiu-e, 

 and false bedding with westerly dips, all in places more or less obliterated in 

 the contortions produced in connection with the deposition of the second till. 



Again, the ditch almost continuously cut across the same sands, overlain 

 and underlain bv till and in jdaces confusedly intermixed with the second 

 till, as it continued north on the North Amherst road up to tlie western base 

 of Mount Pleasant and 80 rods north of the cellar, where the road goes 

 down a small slope, at the gate of the Mount Pleasant grounds. These 

 sands agree exactly with those before described, and are doubtless a con- 

 tinuation northward of the same stratum which I have traced from College 

 Hall and which here crosses the road and runs eastward into Mount 

 Pleasant, What course it takes from here on is uncertain, as it conforms 

 itself to the irregular surface of the underlying till. It seems to me prol)- 

 able that it rises high euougli toward the north or to the east to produce 

 the head and strong flow of water in the wells on the ridge mentioned 

 above. That this water sets from the north to the south was shown very 

 clearlv bv the fact that for 40 feet south of an old well which had been sunk 



