A MONTH WITH THE MCIR GLACIER. 45 



unequal lengths, the western one being about four miles 

 wide, and extending seven or eight miles (estimated) in the 

 direction of the main axis of the bay to the northwest. The 

 eastern, or Muir Inlet, is a little over three miles wide at its 

 mouth, and extends to the north about the same distance, 

 narrowing, at the upper end, to a little over one mile, where 

 it is interrupted by the front of the Muir Glacier. The real 

 opening between the mountains, however, is here a little over 

 two miles wide, the upper part on the eastern side being oc- 

 cupied with glacial debris covering a triangular space be- 

 tween the water and the mountain about one mile wide at 

 the ice-front and coming to a point three miles below, be- 

 yond which a perpendicular wall of rock one thousand feet 

 high rises directly from the water. The mountain on the 

 west side of Muir Inlet, between it and the other fork of the 

 bay, is 2,90(J feet high. That on the east is 3,150 feet high, 

 rising to about 5,000 feet two or three miles back. The base 

 of these mountains consists of metamorphic slate, whose strata 

 are very much contorted — so much so that it is difficuk to 

 ascertain their system of folds. Upon the summits of the 

 mountains on both sides are remnants of blue crystalline 

 limestone preserved in synclinal axes. In the terminal mo- 

 raine deposited in front of the glacier on its eastern side are 

 numerous bowlders of very pure white marble brought clown 

 in medial moraines from mountain valleys several miles to 

 the east. Granitic bowlders are also abundant. 



The width of the ice where the glacier breaks through 

 between the mountains is 10,664 feet — a little over two 

 miles. But, as before remarked, the water-front is only 

 about one mile. This front does not form a straight line, 

 but terminates in an angle projecting about a quarter of a 

 mile below the northeast and northwest corners of the inlet. 

 The depth of the water three hundred yards south of the ice- 

 front is (according to the measurement of Captain Hunter, 

 of the steamer Idaho) 516 feet near the middle of the chan- 

 nel ; but it shoals rapidly toward the eastern shore. A meas- 

 urement reported to me by Dr. Jackson, made in July, 



