THE SPEINCFIELD LAKE. 701 



Farther south, where the road from the vilhige crosses Fort River at 

 the brick ;jits, tlie foUowing section was taken from the exjjosure in the pit 

 and from a well adjacent: 



Feet. 



Fine sand 6 



Clay 35 



Till 



Pockets of pebbles were found in the clay, and the water, very sul- 

 phurous and irony, came to within 5 feet of the surface. Fossil leaves 

 occur here. 



CLAYS IN THE SPRINGFIELD LAKE. 



There are no brickyards in Agawam and West Springfield, though the 

 clay crops out at Riverside. There are extensive brickyards along the east 

 side of the river at the following points: Above the Holyoke In-idge; at 

 Willimansett; in the northern part of Springfield; and especially beside 

 the Boston and Albany Railroad in the southern part of Springfield, and 

 across the line in Longmeadow. 



Eastwardly the clays are deeply covered by the thick sands of the 

 Chicopee River delta, which extend across Wilbraham and Springfield. 



CONTACT OF THE CLAYS UPON THE TILL. 



The section exposed at the hoe factory in Northampton, and illustrated 

 in fig. 31, p. 540, not only shows the contact of the till upon the sandstone 

 and the upper sm-face of the former, upon which the ice rested, but also 

 demonstrates that the deposition of the clay followed immediately upon the 

 disappearance of the ice, under circumstances which indicate that the ice 

 could not have melted in place upon the till; nor could the till have been 

 exposed to subaerial erosion before the clay began to be deposited. In the 

 former case a loose deposit of upper till must have intervened over the till 

 and sandstone alike; in the latter, the till would have been eroded below 

 the level of the sandstone, and the common unifonnly curved surface would 

 not have been preserved. 



It seems to me probable that at this time — the end of the Glacial period 

 for this basin — the waters stood over this place, which is about 135 feet above 

 the sea — and of course over the whole basin — at a height so great that the 

 ice was at last buoyed up and floated awav, and the clays began immediately 

 to be deposited upon the sui'face thus abandoned. 



