102 GLACIOLOGY 



CAPE ROYDS, EREBUS, CAPE BARNE, TURK'S HEAD, GLACIER 

 TONGUE, HUT POINT, AND MINNA BLUFF EVIDENCE 



Glacial conditions, past and present, were especially studied by us in the neigh- 

 bourhood of our winter quarters at Cape Royds. The observations of Ferrar and Dr. 

 E. A. Wilson had made us familiar with the fact that Ross Island shows evidence of 

 two distinct types of glaciation. The first is the glaciation effected in former times 

 by the Ross Barrier, when its surface stood fully 1000 feet above the present level 

 of McMurdo Sound, and when its northern edge extended at least as far north as 

 probably Cape Washington. Even at the present time the southern side of Ross 

 Island, between Cape Armytage and Cape Crozier, is being subjected to glaciation by 

 the northern edge of the Ross Barrier. That this g'laciation is still active is evident 

 from the immense crevasses and pressure ridges at the meeting-point of the Ross 

 Barrier cliff" and the rocks of Ross Island on Cape Crozier. The pressure ridges 

 already figured by Scott and Ferrar near Pram Point also indicate active glaciation 

 still in progress in that region. 



This glaciation of Ross Island, effected by the Ross Barrier, has left most interest- 

 ing traces of the former presence of the ice sheet in the form of deeply trenched elon- 

 gated rock basins, now occupied by lakes, as well as by magnificent terraces covered 

 with blocks of granite, schist, gneiss, Beacon Sandstone, &c., transported as small 

 to large boulders from the old land masses of the mainland to the south and west. 

 During the maximum glaciation Ross Island must have stood out from the surface of 

 the Ross Barrier as a huge nunatak. The flotsam and jetsam from this great ice 

 flood has formed the remarkable terrace near the one thousand feet level. When one 

 surveys the small rock basins, some scooped below sea-level, such as Sunk Lake, Deep 

 Lake, &c., as well as the canal-like grooves cut in a meridional direction through the 

 kenyte lava, one cannot but be impressed with the considerable erosive power of thick 

 glacier ice, thrust forward by the enormous glaciers Avhich fed it to the west and 

 south. 



Secondly, there is evidence of a local glaciation still in progress. This is due to 

 glaciers formed from snow precipitated on the surface of Ross Island, as well as to 

 drift snow which has streamed over the surface of the Ross Barrier, and has then 

 escaped seawards towards McMurdo Sound, over the long volcanic ridge which 

 extends northwards fi:"om Cape Armytage to beyond Glacier Tongue, a distance of 

 about 15 miles. One would, therefore, expect to find, at Ross Island, the glaciers 

 most active where there is now the heaviest precipitation of new falling snow, as well 

 as of drift snow derived from earlier falls. The parts of Ross Island nearest to 

 Ross Sea and McMurdo Sound receive a small snowfall, at Cape Royds equal to 

 perhaps about 7 inches of rain (rain never actually falls in this region, but the 

 measurement of the snow is given in its equivalent of rain). As a matter of fact, 

 Mount Bird and the coast-line from there to Cape Crozier is more or less burled 



