664 GEOLOGY OF OLD HAMPSHIllE COUNTY, MASS. 



THE MOKAINE AOKOSS THE SOUTHERN PART OF THE GRANBY PLAIN. 



Noi-tli of Ludlow, ill the south part of Graiiby, is a phiin about a mile 

 square. It is the south end of the great Grraiiby plain, and is bounded on 

 the east by the valley rim and on the west and south by elevated ridges of 

 till, which at the southwest corner leave open a narrow passage b}^ which 

 one passes from this plain out onto the broader plain of finer sand that 

 extends down to the Chicopee and across west to the Connecticut River. 

 A brook has occupied this narrow gateway, and its flood plain is just wide 

 enough to render it slightly uncertain whether the larger plain formerly 

 extended contiuuouslv through and joined the inner plain at a common 

 level. The difference in level, if any exists, is very slight, and the inner 

 plain is at its south end about 260 feet above sea — a level plain of medium- 

 grained sand. Fifty rods north the sand changes to a 2-inch gravel, in 

 another .50 rods to a 3-inch gravel, in the same distance again to a 4-inch 

 gravel; and it has risen in this distance to 298 feet. It preserves its even 

 surface for another 50 rods, and then suddenly drojjs down into a series of 

 great kettle-holes, which continue a hundred rods and end against a moraine 

 (t m) that stretches right athwart the plain from east to west, not reaching 

 its border on either side. It is unlike any other deposit in the valley, and 

 seems exactly like a terminal moraine. The sands swing round it on either 

 side and extend north, with here and there a depression, but much more 

 regular than immediately south of the moraine. I can not quite understand 

 this, or its time relation to the lake sands, but have expressed on the map 

 the most probable solution of the matter. 



KETTLE-HOLES AND THE OLD RED OF THE CONNECTICUT. 



As a result of the fact that about all the material which went to fill up 

 the lake came from the east side, at the beginning through the Belchertown 

 notch, later from the Chicopee River, the Connecticut found itself pressed, 

 on the shrinkage of the lake, to its western border; and it has excavated its 

 channel so near that border that from Smiths Ferry to Holyoke there is 

 only a trace of the lake deposits left on the west of the present stream; and 

 in all this distance the river has cut a new bed down into the sandstone, 

 while across Chicopee it has cut its bed largely in till. (See PI. XI, p. 510.) 

 Its present bed seems to coincide with the old one nearly down to Smiths 



