J. D. Dana—"Kames” of the Connecticut River Valley. 467 
But the ridge-like feature of many of these coarse upper de- 
posits, on the riverward part of the terrace-formation, that is, 
their standing up 15 to 60 feet. above the level of the terrace 
around, and sometimes higher, is in part, if not chiefly, due to 
erosion. The Norwich stony ‘deposit, on the top, south of the 
Pompanoosue, has a large and broad depression west of it; and 
so has that south of White River Junction, that of Hanover, and 
others. Even the little knoll described on page 463 has its ad- 
joining depressions, as shown in the figure there given, and the 
gulch descending from the southern one of these depressions 
may be a further consequence. The waters of rains, making 
rills or streamlets, easily remove the sand and fine gravel of the 
terrace-formation; but they make comparatively little impression 
on the beds of coarse gravel and cobble-stones, because of the 
size of the stones and ofte sini their partial consolidation by 
iron oxide (limonite). ETeti e the waters which fall over he 
stony surface find a place of dissed and wear away on either 
side ; and with every new inch of descent gained there is a gain 
in fall and foree, and a quickening of the work of erosion. 
The channel begun is deepened and widened, “waters from the 
plain flowing in and helping in the removal; and thus broad 
channels like river-channels may form over id plains, and 
more of depth, and large denudation in some parts would have 
been the consequence. 
he above rh all have reference to those so-called 
" rietl examined by me in the Connecticut River valley. I 
make no i eeping application of them to those which have ee 
described from other regions that I have not seen. It wa 
purpose to have studied, the past season, also the veined of 
the Merrimack valley, but time faile 
The gravel ridges of the vicinity of Aiea, Massachusetts, 
b 
represent a phenomenon of a different class. I ° guid 
ance of Prof. Wright in a day’s excursion over fiers 
Jed to think, as he does, that these isolated ridges of reenter 
fied coarse gravel and stones are of morainic sub-glacier — 
and, perhaps, lateral. though sub-glacier, moraines, left betw 
bodies of ice that moved southeastward along the depieesions’ 
now marsh- silled_—which exist either si them. But without 
more study of them, and especially of thelr relation to the de- 
posits of the Merrimac Magri I would not express a decided 
Opinion on the question 
