100 



BULLETIN OF THE ESSEX INSTITUTE. 



that the observations of Russell on the Malaspina glacier 

 fountains may afford an explanation of this case, for if 

 the subglacial drainage found its way to the surface of 

 the margin of the ice through a crevasse or hole when the 

 lower end of the subglacial streamway became clogged, 

 a break in the continuity of the esker-fan and the esker 

 would be expected. 



The NewtonviUe- Woodland ivcii^h-jjlains . — The Newton- 

 ville esker-fan described b\'^ Professor Davis and modelled 

 by Dr. Gulliver lies south of the 

 Charles River apparently in line with 

 larger wash-plains lying between 

 Woodland and Waban stations on the 

 west. The Woodland plains are com- 

 plex in structure, showing the phe- 

 nomena of ice-retreat and the over- 

 lapping of newer plains on those 

 previously laid down. 



Southeast of Waban station stands 

 a ridge of gravel and sand with an 

 ice-contact slope on its northwestern 

 face with typical coarse detritus in the 

 contact zone. The opposite side of 

 the ridge is lower, slightly lobate, and the detritus finer. 

 The inclined snrface of the deposit suggests that we have 

 in this case an alluvial cone built at the ice edge. The 

 deposit is lengthened parallel with the ice contact. 



The Cambridge moraine and jj/ain. — Old Cambridge 

 lies upon a plain of sand whose northern limit is a well 

 defined ridge extending from Porter's Station southwest- 

 wards by the Harvard Observatory and thence westwards 

 along the southern border of Fresh Pond to the Water- 

 town line. 



This ridge rises at three points to the uniform height 



Fig. 5. The Mechanics- 

 vllle wash-plain with the 

 eeker-llke deposit north of 

 It. The " notch " between 

 the esker and the plain 

 is followed by a stream 

 and is occupied by a pond. 

 (Topography fi-om Frank- 

 lin atlas sheet, U. S. Geol. 

 Survey.) 



