Conjigu ration of the Coasts. 25 



beaches about Yakutat l>ay,'^^ indicating that the land there has 

 risen, whereas the submerged trees in Muir inlet show that this 

 region is sinking. These striking facts seem to show that the 

 valley between the Fairweather mountains and Glacier bay fol- 

 lows the line of an immense fault, which brings Tertiary and 

 Paleozoic rocks into close juxtai^osition. It is most unfortunate 

 that we have no observations on the Fairweather mountains that 

 will enable us to confirm or correct this interesting indication. 



Glacier Bay and Muir Inlet. 



Glacier bay itself has not lieen survej'ed ; the delineation in the 

 coast survey charts is correct only in its general outline. It 

 trends northwest and southeast, and is about forty miles long by 

 ten wide. There are a great many islands in the bay. The 

 Beardslee islands, which fill the eastern side for a distance of 

 about twenty miles from its mouth, are made up, at any rate in 

 })art, of modified glacial till, and are generally thickly wooded, 

 as are also the shores in the lower part of the bay. The channels 

 between these islands are narrow, and often give one the im- 

 pression of waterways cut through the land. The islands in the 

 upper part of the bay are quite different ; they are of solid rock, 

 and are scored, polished, and rounded by glacial action. They 

 occur singly, are usually elongated, and have the longer axis 

 parallel to the nearest shore. They, like the mainland, descend 

 abruptly into the water, and only at long intervals can even a 

 small beach be found. In this part there are no trees. Several 

 glaciers force their way down to the water level and discharge 

 bergs into the bay ; most of them end in narrow inlets two or 

 three miles back from the bay proper. Muir glacier is of this 

 type ; its inlet, which runs nearly north and south, has its south- 

 western terminus on Glacier bay about five miles from the end 

 of the glacier; the eastern shore line rounds gradually into the 

 bay without well marked headlands. The inlet gradually nar- 

 rows as we approach the glacier, being about one and a half 

 miles wide at its upper end. On each side are deposits of 

 roughly stratified sands and gravels, covered with a thin layer 

 of moraine debris. On the western side these deposits form a 

 comparatively level plateau from 150 to 200 feet high, which 

 extends about four miles south of the present ending of the gla- 



* Op. cit., p. 82. 



