SOME GLACIAL WASH-PLAINS. 



83 



the Robin Hill district, near Providence, R. I., not infre- 

 quently show wet weather gullies on the convex brow of 

 the slopes, with alluvial fans converging in the bottom of 

 the pit. These gullies have the appearance of recent 

 origin. I owe the suggestion to Prof. George F. Wright 

 that a very recent melting out of buried ice might give 

 rise to changes now going on in the drainage of areas oc- 

 cupied by kame kettles. A kame-kettle recently formed 

 would for some time be subject to marginal gullying. The 

 observed results meet the ex- 

 pectations from theory ; but 

 the duration of the postgla- 

 cial epoch has been so long 

 that one's judgment, perhaps 

 wrongly, rejects the conclu- 

 sion that buried glacial ice still 

 lingers in this field. i 



Inliei's of older drift. — The 

 contour of the wash-plains is 

 frequently broken by knobs of 

 coarse gravels or by till knolls 

 and small drumlins. Both 

 kames and eskers may be part- 

 ly buried under the growing edge and rising level of the 

 wash-plain. These features of deposition are illustrated 

 in the area on the west of the Boston & Albany Circuit 

 Railroad between Woodland and Waban stations. The 

 Newtonville esker-fan encloses older knobs of drift. 



Irregularities in texture and structure of plains may be 

 largely explained as the result of the burial of drift de- 

 posits previously laid down. These abnormal textures are 

 invariably coarser than the detritus in the body of the plain. 



Fig. 2. Ice-block holes near Aga- 

 waiii River, giviug rise to three lake- 

 lets in a larger depression. (From 

 Plymouth atlas sheet, U. S. Geologi- 

 cal Survey, topography by Grambs, 

 Smyth and Thompson.) 



iSee the literature concerning the ice wells in Vermont. Report of the com- 

 mittee appointed to examine the frozen well at Brandon, Vt. Proc. Boston Soc. 

 Nat. Hist, viil, 186-i, pp.7'2-88. 



ESSEX IMST. BULLETIN, VOL. XXIX 6* 



