!"».! V S. SHALES — DEPOSITB OF EASTERN MASSACHUSETTS. 



1,900 and 2,400 feet from the datum point. < >thergrea1 folds doubtless exisl 

 in the section, as is Bhowo by the facl that at 1 ,.'>()< i feet the greensand and 

 associated beds exhibit the series in reversed order. This fold probably re- 

 turned through the eroded portion of the beds to Bome point in the covered 

 portion of the escarpment from o(H) to loon t * - * - 1 to the east. There is an- 

 other great fold obscurely indicated near the Devil's den, the extension of 

 which is as yet undetermined. Although a number of faults are indicated 

 in the section, there are doubtless others which have escaped observation, 

 1 n no other way than by a combination of faults with folds can the frequenl 

 inversions exhibited in this diagram be explained. 



It will lie observed that over a good part of this district the glacial drift 

 is not traceable. I ts absence is conspicuous between station 4,100 and the 

 end of the section. The drift also exists in the area near the wharf, but it 

 was not delineated because the escarpment was grass-covered and it was dif- 

 ficult t<> discriminate the glacial from the lower-lying deposits. 



Between stations 2,000 and 2,100, at a height of 80 feet above the sea, a 

 small patch of interglacial or preglacial deposits containing abundant frag- 

 ments of shells of living species was found. As the portion of the deposit 

 which remained did not contain more than lo or 15 cubic feet of material, it 

 was impossible to determine its exact relation to the remainder of the section. 

 It is possible that the material came into it> position by sliding from a more 

 elevated position. 



It give- me pleasure to Btate that 1 am indebted to several students of 

 Harvard University for assistance in the preparation of this paper. A large 

 part of the detailed work was done by Mr. J. R. Woodworth. The whole 

 of the sections contained in the plate were drawn by him, and the greater 

 part of the recent field work on this escarpment is due to his labor. 



