TUB HIGH TERKACE IN GUEENFIELl). 633 



West across the high phiiu (Fraukhu Park), t'roiu tlie tup of this sec- 

 tion to where the raih-oad again cuts into it, the sands rise in heavy beds 

 by a long and slighth' curved sweep from north to south. These two sec- 

 tions he just south of the south end of the great Green River depression 

 mentioned above. To the west the wall rises unbroken, and there is no 

 chaiuiel down which a considerable stream could have come. 



It seems to me that the sands have here been built up to this high level 

 by the water from the Bernardston Pass and Factory village channel 

 coming down over the ice which filled the Green River basin. It is difficult 

 to see how they can have come from any other direction, and equally diffi- 

 cult to see how they can have been built up here to a broad plain of the 

 height of the high terrace while the aliove basin remained open and unfilled 

 to the north. 



The clavs appear alnindantly in the south half of Greenfield, where 

 they are used for brick making, and rest on sandstone or till. Farther south, 

 in the southwest corner of the Deei-field River basin, Avhere a brook has cut 

 back in the rim of the basiu, is a great exposure of these clays, which for 

 a distance of about 12 feet down from the surface and about the same in 

 from the basset edges of the horizontal beds, have weathered to fine buff 

 clavs, while the interior is the ordinary blue clay. 



Farther south the u])per surface of the claj's is marked for a long dis- 

 tance by a line of springs in the Idufts along the west side of the basin. 

 Before reaching the mouth of the gorge of the Deerfeld River, however, 

 the clays change into fine sands, and the upper sands also grow finer, and in 

 the southern bluffs of the erosion basin the whole thickness of the old delta 

 of the Deerfield River is made iip as illustrated in the Wapping cutting (see 

 PI. XYIII, p. 694) by 50 feet of the very finest sands, and this continues 

 to be the character of the great body <>f sands which fill the Deei-field 

 Valley south through Deei-field and Hatfield. 



It seems probable that the delta of Deerfield River was thrust across 

 the valley to abut against Deei-field ^lountain u})on the east, and was 

 elevated more rapidly than the deposits to the north in Cheapside and 

 Greenfield, so that a quiet area of deeper waters exi.sted here, in which the 

 clays were laid down; and later, the current increasing, the horizontal 

 sands were carried in over them, proljabl}' through the pass from Turners 

 Falls; and at last the heav}" floods of the hightest water stand through the 



