GLACIAL DRIFT. 



279 



museum. About two miles north of Norwich village, Vt., on the road to 

 Copperas hill, is a hill thirty feet high, of lower till with innumerable 

 glaciated stones cemented by boulder clay. One of a micaceous argillite 

 may weigh 1500 pounds, perhaps five feet in length, of the typical trap- 

 ezoidal shape, except it is narrower than usual. The longer axis points a 

 little east of south, as the stone lies in the bank. The under surface and 

 the sides are striated parallel to the longer axis, but the upper surface 

 bears very plain marks at right angles to those beneath. I was able to 

 preserve only a piece of this boulder, showing the upper surface and the 

 beginning of the lower strias at right angles to them. The boulder 

 proved larger than was expected, so that I could not transport it entire 

 to Culver Hall. 



A common variation in shape is the elongated narrow one, a prolate 

 spheroid. Geikie, in his work on the Great Ice Age, figures four striated 

 stones from Scotland, three of which clearly possess the typical shape I 

 have mentioned, while the fourth is blunt at one end and pointed at the 

 other, — a form also seen with us. These stones show the same features 

 the world over. Argillaceous boulders best preserve the glaciation. 



Surface Deposits at Portland, Me. 



The relations of the two varieties of till to the Champlain gravels are 

 not exhibited in any outcrops yet discovered in New Hampshire. A 

 familiarity of long standing with the fossiliferous clays and the drift of 



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3> =¥^-,,'=?.-Xs' ^"^.V^ 



Fig- 59- — Section in Till, Portland. 



a. Upper till; b. Fossiliferous Champlain beds ; c. Lower till. 



Portland, Me., led me to think the question of relative position well 

 shown there; and upon examination I discovered that the fossiliferous 

 beds occupied a place midway between the two kinds of till. Numerous 

 excavations have made the sections in the till and sands perfectly satis- 



