86 The American Geologist. August, 1899 
northern United States as to their relative area, in comparison 
with rock formations yielding principally clay or fine rock 
flour. It need not surprise us, therefore, when we encounter, 
adjoining the front of the outermost marginal moraine belts of 
this region, exceptionally abundant overwashed deposits of 
gravel and (mostly) sand. These frontal plains reach south 
from the moraines, with a gentle descent, to the sea. In keep- 
ing with this great development of modified drift borne by the 
waters of rains and glacial melting beyond the ice border, it is 
equally noteworthy that the outer moraine for a distance of 
more than seventy-five miles on Long Island, from Roslyn to 
Napeague, consists almost wholly of massive hills of gravel 
and sand, with only few boulders or none. So long a section 
of any terminal moraine built up of modified drift is unknown 
in the interior of the country, but in some places the same char- 
acter prevails for a mile or a few miles. Likewise the frontal 
plains which in this district, on the south side of New England, 
are grandly displayed along distances of scores of miles, have 
their analogues for a few miles at many places all along the 
course of our great system of continental moraines from north- 
ern New Jersey to the Dakotas. One tract where I have seen 
them well developed is along the south side of Devil's lake, in 
North Dakota. These plains of Long Island and southeastern 
New England are crossed, as already mentioned, by ancient 
stream courses which originated during the deposition of the 
plains, proving this to have taken place, as I maintain, above 
the sea level. 
Earlier gravel, sand, and clay deposits, which are largely 
represented on the New England islands and the Cape Cod 
peninsula, named by Shaler, in their order of age from the 
older to the newer, the Nashaquitsa series, the Barnstable and 
Tisbury or Weyquosque series, and the Truro series, I think 
to be all modified drift discharged from the ice-sheet by its 
superglacial and subglacial streams. Professor Shaler sup- 
poses the massive ridges and plateaus of these formations, 
overspread on the north by glacial drift, to be remnants spared 
by erosion from an extensive sheet of these deposits that once 
reached a considerable distance inland with similar thickness. 
I believe instead that these tracts owed their limits to unmelted 
portions of the ice-sheet existing on each side at the time of de- 
