GLACIAL DRIFT, 



291 



Kingston, — lenticular mass, on south-west 



side of Great hill 



East Kingston, — lenticular mass, on south- 

 east side of Great hill 



Kensington, — Moulton ridge, lenticular hill, 



at top 



I mile south of last 



Top of lenticular hill, south of Muddy 



pond 



North-west slope of same hill 



South Hampton, — north-west village 



n. Two or three seams of sand, in- 

 clined 45°, 3-6 inches wide and several 

 feet long, occur in the lower till, which is 

 underlain hy a stratum of black clayey 

 sand I foot or more in thickness. 



a. Upper and lower till separated by 

 a layer of sand 4 inches thick. 



/. Upper and lower till separated by 

 6 inches of waterworn gravel. 



The average thickness of the upper till, obtained by taking the mean 

 of these observations, is three feet and nine inches. If we subtract one 

 tenth of this, due allowance will probably be made for areas that are 



Fig. 61. — Section of Glacial Drift, two miles east of Ashland, 



illustrating the usual mode of occurrence of the upper and lower till 



throughout the state. 

 Thickness of the upper till, 4 feet ; of the lower till, 25 feet. The most 



abundant boulders in the former were porphyritic gneiss ; in the latter, 



Montalban. 



destitute of this deposit, leaving three and one third feet, which would 

 thus appear to be approximately the mean depth of the upper till, if it 

 were spread in a sheet of uniform thickness over the entire state. 



The lower till, however, does not appear to have any development 

 upon half of this territory, being accumulated in patches, sheets, and 

 lenticular masses, while over adjoining areas of equal extent the ledges 

 are exposed or covered only by the upper till. Very few of these sec- 

 tions show the whole thickness of the lower till ; and its depth in the 

 lenticular hills affords no basis from which to judge of its other deposits. 

 It is impossible, therefore, to arrive at an estimate, as before, from this 

 table. If we still wish to form some conclusion respecting the entire 

 mass of the ground-moraine, it will be well first to consider the lenticu- 

 lar hills and slopes, of which about eight hundred and sixty have been 



