218 T. C. CHAMBERLIN — GLACIAL STUDIES IN GREENLAND. 



glacier was seen overriding its terminal moraine in one portion and re- 

 treating within it at another. This, taken in connection with the massive- 

 ness of the moraine, probably indicates that it has stood practically 

 stationary for a considerable period. 



The most remarkable evidence relative to former extension is furnished 

 by a driftless area on the east side of Bowdoin bay immediately adjoin- 

 ing the present great ice-cap. It is obvious that at this point the ice is 

 as far advanced as it has ever been in the recent geologic history of 

 Greenland. The verity of this driftless area is attested not only by the 

 absence of transported material upon it, but by the exceedingly angular, 

 ragged disintegration of the harder terranes of rock embraced in the com- 

 plex gneissic series and by the deep disintegration of the gneiss itself. 

 The gullies and ravines reveal the fact that the gneiss is deeply decom- 

 posed to a soft, rotten mass, which is not only easily crumbled, but is 

 even pliant under the fingers. It was possible to descend steep slopes by 

 thrusting the heels deep into the softened mass. The combined weight 

 of all this evidence puts beyond serious question the verity of the drift- 

 lessness of this region. The area is small, not exceeding three or four 

 miles in maximum diameter, and lies between the ice-edge and Bowdoin 

 bay on ground whose average altitude is less than that of the glacier, so 

 that its immunity from glaciation has not been due to elevation. It is 

 clear, therefore, that the ice-border was stayed at this point by agencies 

 concerned in its own development and not by any topographic barrier. 



Immediately at the south of this small driftless area there lies in front 

 of the Gable glacier (which is but a short tongue of the main sheet) a 

 stout old moraine, the surface of which has been notably weathered and 

 has become covered with vegetation in the scant fashion of the region. 

 There is nothing in the nature of this moraine to indicate an antiquity 

 beyond perhaps a few hundred years, but its presence at this point seems 

 to indicate that the ice has stood in the vicinity for a considerable period, 

 and therefore that it is probably, on the average, neither much advancing 

 nor much retreating. 



Former Extent of Glaciation. 



It is evident that the occurrence of even a small driftless area on a 

 border of the widest stretch of the Greenland ice-sheet is extremely sig- 

 nificant respecting its former extension. The general scantiness of the 

 drift over the territory immediately outside of the present ice seems also 

 to raise doubt as to any great former extension. There are two other 

 lines of important evidence that bear upon this question. Dalrymple 

 island is a mass of hornblendic gneiss rising from the water's edge to a 

 height of perhaps 100 feet, with steep slopes and ragged surfaces. It is 



