37 
Prof. T. C. Chamberlin. 
Glado-Natant Phenomena. 
Under this convenient term may be embraced all forms of float- 
ing ice and all kinds of geological action arising from such ice. 
The convenience of grouping these together lies in the frequent 
need of distinguishing them from land ice, glaciers in particular. 
ICE FLOES. The simplest kind of natant ice encountered 
was that which was formed by the freezing of the sea surface dur- 
ing the preceding winter. This we met in more than its usual 
extent and thickness in Melville Bay and Inglefield Gulf. As it 
presented, however, no wide departure from the oft-described 
characteristics of such ice, it need not detain us. On the imme- 
diate coast it is obviously a geological agency of some moment, 
particularly where the tides are strong. In such situations the 
ice rises and falls semi-diumally, and so is caused to work ef- 
fectively upon the shore with which it is in contact. To a consid- 
erable extent, however, the shore is protected by a fringe of sta- 
tionary ice which acts as a buffer against the tide-actuated ice. 
As the summer advances, however, this skirting ice yields and be- 
comes itself an instrument of the tide. The geological effect lies 
chiefly in the grinding of the shore material. There is a limited 
amount of transportation of the material backward from the 
shore by reason of its attachment to the ice. When it is consid- 
ered that the ice during a large portion of the year acts as a pro- 
tection to the shore, it may be an open question whether the 
eroding and transporting activity is at all increased by the agency 
of the ice when the yearly average is taken. The action takes a 
different form and is interesting and important from that point of 
view. 
Closely allied to the relatively thin floes — rarely more than 
five or six feet — formed unquestionably by the freezing of a single 
season are the sheets that are retained from year to year and 
given additional thickness. There is little of this formed in Baf- 
fin Bay, although the ice is not entirely cleared away each sea- 
son. As a result the Baffin floes are relatively thin, lie low in 
the water and have a flat surface, except as crushed up at the 
edges by mutual encounters. 
