ICE OBSERVATIONS. 197 
has been suggested that an abundance of included material may 
greatly retard, possibly even arrest, the movement of the lower 
layers. Sketches or photographs of them should be taken, 
(3) If any fine streaks are present, their direction, number and 
arrangement should be noted. 
(4) Specimens should be collected of any included rock fragments 
or mud, 
Such observations can be taken better on the face of the Barrier 
than on its surface; and the same rule is applicable to the study of 
all forms of ice. In crossing the upper surface of the Barrier, the 
most important point to observe is the arrangement and distribution 
of the crevasses. 
It would be interesting to know the area of the Ice Barrier and 
the direction of its movement. 
IV. Lanp Ics. 
The Land Ice will probably be found to consist of inland ice 
sheets and of tributary valley glaciers. 
In addition to a general topographical description of the forms 
and distribution of the ice, observations may be made on the 
following lines: 
(1) Glacier Terminations—These will probably be either vertical 
faces (Chinese Walls) or tapering snouts. The directions towards 
which they face should be noted, and several of the ‘Chinese Walls’ 
should be studied in full detail. Observations should be made of the 
structure and thickness of the successive layers; the amount of and 
nature of the material included in the different layers of the ice; the 
overhang, if any, of the top layer; the mode of advance of the glacier 
as a whole; the effect of the advancing glacier on obstacles in its 
path, such as the moulding and sculpturing of the rocks over which 
it passes ; whether its action is erosive as well as abrasive, and how 
far such action is dependent on the magnitude of the ice stream, and 
on the slope, or changes in the slope, of the surface over which it is 
passing. In some cases a glacier appears to advance over a causeway 
of its own building; that is, by overriding its own terminal moraine 
(constructed in Greenland very largely of material transported in the 
lower part of the ice); in other cases, probably dependent very largely 
on the amount of the slope, it thrusts the material before it. The 
effect of subglacial streams and the arrangement of the ice beside 
their channels should also be studied. 
