GLACIATION OF WRANGELL MOUNTAINS 



47 



Feet, 



20' Conce&led. 



region, the Chisana trough has very evidently been occupied at no 

 very remote period by a glacier of much greater extent than the present 

 one. It pushed from the Wrangell Mountains northeast through the 

 Nutzotin Mountains to their nortli base, and was very deep through- 

 out the valley. On Euchre Mountain there are moraines and erratic 

 bowlders up to the 6,600-foot level, or 2,500 feet above the terminus 

 of the present glacier, and in the low col west of this mountain there 

 must have been at 

 least 1,200 feet of ice 

 which moved northward. 

 Euchre Mountain at that 

 time was an island stand- 

 ing about 1 ,000 feet above 

 the surface of the sur- 

 rounding glacier. East 

 and northeast of Euchre 

 Mountain the ice was not 

 confined by steep valley- 

 walls, and doubtless 

 spread out into a wide 

 lobe at this place. Below 

 Chavolda and Cross 

 creeks it was again 

 compressed to a narrow 

 tongue in the canyon- 

 like valley through the Nutzotin Mountains, and probably again 

 deployed on the plain to the north of this range. 



At the cHmax of this glacial period, each tributary valley of the 

 Chisana, both in the Wrangell and Nutzotin mountains, was occupied 

 by a glacier which joined the body of ice in the main valley. It is 

 probable that the whole mountainous area had much the same appear- 

 ance at that time as that shown by the higher parts of the Wrangell 

 Mountains now (see Fig. 4). 



Since the retreat of the ice to its present position, the greater num- 

 ber of tributary valleys have been deglaciated; and only the higher 

 and more favorably situated summits have perennial ice upon their 

 flanks. 



25 Fine stratified j^rave I 

 Pebbles 5" or /ess in 

 diameter. 



15' Coarse jgravel. Bowlders 

 ia"op /ess in diameter. 



Fig. 6. — Section of gravel terrace on the 

 Chisana River, lo miles below the mouth of 

 Chavolda Creek. 



