MODIFIED DRIFT ALONG MERRIMACK RIVER. 93 



is 75 to 100 feet above the river, whicli is liere 93 feet above the sea. 

 The modified drift of the next half mile southward, extending to an ex- 

 posure of the till, consists of a level gravel plain, 75 feet above the river, 

 which contains pebbles up to one foot in diameter. This very coarse 

 alluvium has a greater height than the finer deposits west of the river. 

 It seems to be of earlier date than these plains, or even than the kames 

 northward, and was probably formed in the same way with the latter, dif- 

 fering only in its greater extent. 



In Nashua, excavations have been made in remnants of the kames on 

 the north side of Canal street, and on the west side of the Nashua & 

 Lowell Railroad, a quarter of a mile south from the Concord depot. A 

 short series seems to extend from the latter point to the south-west, 

 principally concealed by later deposits. A mile and a half farther south, 

 near the city farm, we find another ridge which has been excavated for 

 gravel at its north end. This extends south-easterly nearly continuous 

 for a mile, and is from 20 to 40 feet high. The road lies parallel with it 

 on its north-east side for four fifths of this distance, but at length turns 

 to the south, crossing the kame and rising above the alluvial area, of 

 which this ridge forms the border. The material of these ridges is 

 water-worn but quite coarse, containing stones up to one and a half or 

 two feet in diameter. These kames are probably to be regarded as por- 

 tions of a series which was never connected. A mile southward it ap- 

 pears again, here also at the west margin of the alluvium, between the 

 highway and railroad, south of Little's station. The highest of these 

 kames in Nashua does not exceed 100 feet above the river. This series 

 does not ajDpear to extend into Massachusetts. 



Several other deposits of this kind were noticed at the west and north- 

 west within the limits of our map. Fairmount heights, a coarse gravel 

 plain on the north side of Nashua river, west of the city, is a deposit of 

 similar origin with the kames. Near the west line of Nashua, ridges and 

 mounds of this gravel occur on the south-east side of this river. Other 

 kames, forming very coarse gravel ridges, were observed in the north 

 part of Hollis near a school-house and saw-mill, on the south side of Pen- 

 nichuck brook ; and in Amherst, a third of a mile south from the railroad 

 station. Similar deposits, most frequently of small extent, may be found 

 in almost every town in New Hampshire, 



