208 MR. E. J. GAEWOOB & DE. J. W. GEEGORY [May 1 898, 



manner of the car of a switchback. But the upward slope on the 

 margin of Booming Glacier is so great, in proportion to the length of 

 that glacier, that we cannot reconcile the ascent of the ice with 

 any theory of glacial flow. We are therefore driven to regard the 

 depression in the middle of this glacier as due to recent shrinkage. 

 Some of the tributaries to Booming Glacier have not been aflected 

 by the diminished snowfall which has led to the decrease of the 

 main stream. Thus a glacier that flows down from the Baldhead 

 has continued to advance, and is now spreading out over the ice- 

 stream by which it was once dammed back and absorbed. A point in 

 the middle of Booming Glacier, which at one time only received 

 material from the sources of the main stream, now receives a supply 

 from the source of the tributary. If Booming Glacier increases 

 in size, it will again block the lateral glacier, and all the morainic 

 material along its middle line will come from the peaks at its head. 

 Hence, in the deposits of the glacier there would be a layer with 

 boulders from the west, interstratifled between layers in which all 

 the material came from the south. 



III. The Deposits oe the Glaciees. 



The deposits of the Spitsbergen glaciers may be conveniently 

 divided into four groups : — 



(1) Normal moraines of the Swiss type. 



(2) Moraines formed of intraglacial material. 



(3) Moraines formed of redeposited beach-material. 



(4) Glacial gravels. 



(1) Normal Moraines of the Swiss type. 



This division includes moraines formed of material that has 

 been carried on the surface of glaciers^ The boulders of these 

 supraglacial moraines are mainly angular, irregular, and unscratched; 

 they generally occur in ill-assorted material, which is coarse and 

 granular, and in which arenaceous material predominates. A few 

 rounded and some scratched boulders occur, but the proportion is 

 not greater than in an ordinary Swiss moraine. 



Moraines of this character are common in the Spitsbergeii 

 uplands. As examples, we may cite some of those on the flanks 

 of Booming Glacier, one in Esker Valley on the north-eastern side 

 of Brent Pass, and the moraines at the northern foot of Mount 

 Nordenskiold. 



The moraines agree in their general characters with those of 

 existing Swiss glaciers, and there is accordingly no need to describe 

 them. 



We may refer, however, to a case of the formation of crescentic 

 moraines by the Grit Ridge Glacier. A lateral glacier in the valley 

 is depositing a series of crescentic terminal moraines on the surface 

 of the main glacier. These moraines are being carried forward 



