tS 9 2.] 
475 
[De Geer. 
served long since which show that these tracts in very modern 
times have been and perhaps still are sinking, and it is of in- 
terest that these signs of subsidence are found along the Atlantic 
coast plain outside of the glacial region of uplifting as well as 
somewhat within its boundary, just as has been the case in 
Scandinavia. Thus submarine peat-bogs are known in New 
Jersey and Nantucket Island as well as at the northeastern end 
of the Bay of Fundy and at the mouth of Bay Chaleur. These 
last localities show that if the rising of land is still going on in the 
interior, the isobase for zero, or, to use Shaler’s expression, the 
pivot point between the continental upheaval and the oceanic 
subsidence, has moved at least more, than fifty miles toward the 
land side. The amount of this subsidence is not yet known, 
but at the Bay of Fundy it must have been at least 40 feet and at 
Nantucket probably 10 feet. Even the numerous small buried gla- 
cial river valleys at the southern shores of Cape Cod, Nantucket, 
Martha’s Vineyard, and Long Island afford evidence of a slight 
submergence. The same is the case, as Merrill has pointed out, 
with the Hudson River estuary, which must have subsided 
somewhat since the channel was cut out of the glacial clays in 
the valley. 
Another question is whether the deep submarine river valley 
southeast of New York harbor, so well described by Professor 
Dana, belongs to so late a period. The fact that its upper end 
down to a depth of about 100 feet has been entirely filled up at 
the outside of Sandy Hook seems to indicate that the Hudson 
River leveled the adjacent part of the pre-existing channel 
during the maximum of the post-glacial elevation, having its 
mouth here for a considerable time. The other analogous sub- 
marine channel described by Dana from the north side of Long 
Island may perhaps afford a possibility of determining their 
age. Having crossed Long Island Sound in an oblique direction, 
it becomes during the last 10 miles more and more shallow, end- 
ing abruptly at Long Island against the terminal moraine. Here 
it may be possible to ascertain with a few borings, whether the 
channel, as it appears, has been overridden by the moraines of 
the last glaciation, and perhaps also whether it is younger than 
those of the first glaciation. 
Though the abrupt ending of this last channel is very, likely 
due to the terminal moraine, which, to judge from Dana’s obser- 
