566 GEOLOGY OF OLD HAMPSHIEE COUNTY, MASS. 



most abundant and the largest woolsack-like bowlders; on the west its heavy 

 sands and clays overhang the valley of the Quaboag (as the Chicopee River 

 is called above Palmer) and the station of Brimfield, which is 390 feet 

 above the sea. When it was formed the ice must have occupied the whole 

 of Hampden Countv west of this point, and must have filled the valley of 

 the Quaboag, here running north and south, to furnish the western wall of 

 the basin. One standing at the railroad station and looking east can see 

 that the horizon, almost over one's head, is the horizontal line of the front 

 of the high, level sands of this lake, which extend north and south for 

 nearly 2 miles and stretch back east for a mile and a quarter. Just in 

 front of the station, at a large brickyard, a fresh vertical section of 20 feet 

 of horizontal, perfectly sorted yellow sand is exposed. 



In many places a vast number of the great bowlders of porphyritic 

 gneiss have been dropped into the sand from icebergs which separated 

 from the ice front and floated on the lake, and at a distance many slopes 

 produced by erosion look like the coarsest till. They have, hoAvever, 

 everywhere the contour of sand slopes, and are very heavy masses of 

 well-bedded sand. Beneath these sands is the following peculiar section 

 of till: 



Section of clay ut Brimfield station. 



Feet. 



Till with great bowlders ou its surface 6.5 



Brown laminated clay with few bowlders 12 



Blue laminated clay without bowlders, very fine and tenacious ; exposed - 6.5 



These clays seem to be subglacial deposits, or to have been deep- 

 water deposits oveiTidden by a readvance of the ice. The section was 

 taken at the kiln. 



South of this lake are two others belonging in the same series, which 

 may be called the Parksville and the East Monson lakes. The former was 

 half filled from the north by heavy sands tlu-ust forward into its basin as 

 a great delta, whose front scarp is still well preserved as a steep south slope, 

 crevassed at one point by the stream that emptied the lake northwardly. 

 Around the south half of the basin its shore line is hardly traceable. 



THE MONSON ESKER. 



It was perhaps but little later than the time of the formation of Brim- 

 field Lake, while the ice was thnist down the deep, straight valley which 



