The 3Iar(jin of the Cornell Glacier. 141 
Bonsteel I made a journey over the ice to a nunatak which 
rises above the glacier at a distance of eight or ten miles from 
its margin. This nunatak, named mount Schurman,* was as- 
cended, and its contact examined. We therefore obtained a 
rather clear idea of the conditions existing on and at the mar- 
gin of a part of the Greenland ice cap, and also of a single 
great glacier tongue extending from it into the sea. 
Hack Fragments on the Ice Surface. Excepting at its base, 
where it comes in contact with the moraine and the nunataks, 
the ice, so far as seen, was absolutely free of all debris ex- 
cepting of two kinds. Near the sea, and in fact as far as we 
went out upon the ice, to a distance of six or eight miles from 
the terminus, the glacier surface was pitted by the dust wells 
which have frequently been described. These were of impal- 
pable dust, evidently blown from the land. Professor Gill 
has examined some which was collected at a distance of about 
three miles from the nearest land, and under the microscope 
discovered distinct fragments of recognizable minerals. The 
larger pieces are biotite mica, but there are also smaller frag- 
ments of epidote, plagioclase, feldspar and quartz. In the 
specimen examined the largest pieces of mica measured one- 
sixth of a millimeter. This dust .rested in wells of water 
whose depth was usually not greater than eight or nine inch- 
es, though in some cases as much as 15 or 18 inches. In di- 
ameter the wells varied from one-eighth of an inch to several 
feet. The total amount of this dust in an acre of ice would 
amount to only a few pounds. 
The second class of debris was found in only one place, on 
the seaward or down stream side of the mount Schurman 
nunatak. (Plate VI.) This was a moraine of large rock 
fragments, with a considerable admixture of clay, derived 
from the two lateral moraines of mount Schurman. The clay 
element was of minor importance, and at a distance of a mile 
from the nunatak had alm(^st entirely disappeared, being car- 
ried awa}' by water, and removed b}^ the good sized streams 
which flowed over the ice surface parallel to, and along the 
side of the moraine. As the distance increased the moraine 
became more and more attenuated, until finally there was only, 
a narrow band of rock, resting as a mere film on the ice sur- 
*After president J. G. Schurman of Cornell University. 
