8o ALASKA GLACIERS 



The overturned forest trees associated with the push- 

 moraines on the eastern and western shores of the bay and 

 on the island, exhibited the same general appearance of 

 recency, and there can be little doubt that they were dis- 

 turbed at the same time. They demonstrate a temporary 

 increase in the size of the glacier, not of precisely the 

 same amount at all points, but of the same order of mag- 

 nitude. Previous to that expansion the glacier had been 

 smaller during a period at least sufficient for the growth of 

 the overturned trees. The evidence from forests and 

 push-moraines does not show whether the ice during this 

 epoch stood continuously near to the forest or was sub- 

 ject to wide oscillations in extent; but the bending of 

 the moraine belt on the back of the glacier into the 

 western embayment (page 73) gives strong support to 

 the view that the recent maximum was preceded by an 

 important minimum. 



No attempt was made to estimate the age of the trees 

 by counting rings of growth, but the forest had the char- 

 acteristics of maturity, and the time required for its pro- 

 duction could hardly have been less than two or three 

 centuries. The mountain side just west of the glacier, 

 rising steeply to a height of 2,000 feet, is clothed with a 

 luxuriant growth from the push-moraine up to about 1,500 

 feet. Many of the trunks are three or four feet in diam- 

 eter, and among them lie prostrate logs in a state of de- 

 cay. Upon the islands, and on the lowland near the east 

 margin of the glacier, the trees are somewhat smaller, but 

 the many dead trunks standing among them indicate that 

 they are mature, and their term of life may be as long as 

 that of their western neighbors. 



A further item of information as to variation, albeit 

 somewhat indefinite, may be derived from Vancouver's 

 map. It is not sufficiently precise to afford identification 

 of any topographic detail of the bay except Heather Island 



