IN THE WHITE MOUNTAINS. 551 
were the more clear and impressive to me because I was 
then fresh from my investigations of the glaciers in Switzer- 
land. And yet, beyond the mere statement of the fact that 
such glaciers once existed here, I have never published a 
detailed aceount of my observations, for the simple reason 
that I could not then find any limit or any definite relation 
between the northern drift and the phenomena indicative of 
local White Mountain glaciers; nor have I ever been able 
since to revisit the region for more careful examination. 
This year a prolonged stay among these hills has enabled me 
to study this difficult problem more closely, and I am now 
prepared to show that the drift, so-called, has the same gen- 
eral characteristics on the northern and southern side of the 
White Mountains. Whatever, therefore, may have been the 
number of its higher peaks which at any given time, during 
the glacial per id; rose above the great ice sheet which shew 
covered the country, this mountain range offered no obstacle 
to the southward movement and progress of the northern 
ice fields. To the north of the White Mountains as. well as 
to the south, the northern drift consists of a paste more or 
less clayey or sandy, containing abraded fragments of a great 
variety of rocks, so impacted into the minutely comminuted 
materials as to indicate neither stratification nor arrangement 
or sorting, determined by the form, size or weight of these 
fragments. ‘Large boulders and pebbles of all sizes are 
found in it ilirnghéok its thickness, and these coarser mate- 
rials have Writ been ground together with the clay and 
sand under great pressure, beneath heavy masses of ice; for 
they have all the characteristic marks so unmistakable now 
to those who are familiar with glacial action: scratches, 
grooves, furrows, ete. These marks are rectilinear, but 
they cross each other at various angles, thus showing by the 
change in their direction that the fragments on wdiich they 
occur, though held for a time in one amd the same position 
while its straight lines were engraved upon their surface, 
nevertheless changed that position more or less frequently. 
