294 SURFACE GEOLOGY, 



200 feet in height. From its top two prominent hills of this class are seen within a third 

 of a mile on the west. Another fine example was noted about a mile south from these ; 

 two more occur a mile west from the last ; and several were seen in the south-east part 

 of the town, one lying a short distance north-west from school-house No. 13, and others 

 within a mile to the west and south. 



The valley of Thompson brook, in the south-west corner of Alstead and north part 

 of Surry, is bordered by large deposits of till, which at several places have a well defined 

 lenticular form. These hills are also well shown along the Ashuelot valley in Gilsum. 

 In Westmoreland they are numerous along the route of the Cheshire Railroad, occur- 

 ring close north of East Westmoreland depot, at one mile west and south-west, and for 

 one mile to the south. No typical lenticular hills were noticed near Westmoreland 

 village, but similar masses of till rest against a ledgy hill one mile south-west : and at 

 a mile and a half south a broad sheet of it forms the north slope of Pistareen mountain. 

 These hills are very finely shown in Chesterfield, as many as fifty distinct lenticular 

 accumulations being noted. They abound from Factory village west to Connecticut 

 river, being especially numerous and massive within a circuit of one mile about Ches- 

 terfield centre. Only inconspicuous examples occur in Hinsdale ; but Winchester has 

 about a dozen well defined and prominent lenticular hills within four miles north from 

 Ashuelot and Winchester villages. These constitute an isolated group, surrounded on 

 all sides for three or four miles by irregular ledgy hills with no considerable accumula- 

 tions of till. In each of these towns, other areas adjoining those which we have de- 

 scribed are destitute of these deposits. 



The central portion of this county, which has only very rare lenticular hills, comprises 

 the towns of Marlow, Stoddard, Sullivan, Roxbury, Keene, Swanzey, Troy, Richmond, 

 and Fitzwilliam. In Nelson, these hills are found near the village. Several good ex- 

 amples, 50 to 75 or 100 feet deep, occur within a half mile to the south-east and within 

 a mile and a half to the west. In Harrisville and Marlborough a few lenticular hills 

 are noted ; but the greater part of these towns shows no trace of them. 



Their best display in this county is at the south-east, in Dublin, Jaffrey, and Rindge. 

 On the north side of Monadnock mountain they are finely developed, four very promi- 

 nent examples occurring about two miles north-west from Monadnock lake, which is 

 also bordered by small but typical lenticular hills on its north-west side. Their trend 

 here is uniformly from north-west to south-east, or nearly so, while in other parts of 

 this county it is almost always approximately from north to south. This divergence of 

 45° from the usual course was due to deflection of the ice-current, for the strias of this 

 vicinity show the same eastward deviation. Between Dublin village and Thorndike 

 pond numerous lenticular accumulations occur ; but many of them are not true hills, since 

 they rest against ledges at the north. The east half of Jaffrey and nearly the entire 

 township of Rindge are well filled with the lenticular hills, which vary from 50 to 150 

 feet in depth, but scarcely any of them have received special names. Their fertility 

 has caused them to be cleared, and their smoothed fields of pasturage or mowing con- 

 trast notably with the ledgy hills of similar height but very irregular outlines, which 

 abound in tlie next fifteen miles to the west. 



