24 H. F. Reid — jShtdies of Muir Glacier. 



publications of charts and other data making known the more 

 important channels and waterways with ample accuracj'' for, 

 navigation. 



Southeast of the Alaska-British Columbia boundary the 

 islands beconae larger and the waterways wider. Cross sound 

 and Icy strait form the northwestern boundary of the archipelago. 

 From them two deep inlets, Lynn canal and Glacier bay, stretch 

 toward the north and northwest, forming, with the Pacific ocean, 

 two i^eninsulas. The great Fairweather group of mountains 

 occupies the western part of the peninsula between Glacier bay 

 and the Pacific. The east^ern part is occupied by another and 

 much lower range, whose peaks rise about 5,000 or 6,000 feet 

 above the sea. Their northeastern slopes are gradual and are 

 covered with large glaciers, some of which reach tide-water and 

 discharge icebergs into Glacier bay. Between these two ranges 

 there seems to be a deep valley, which drains the eastern slopes 

 of the Fairweather group. This is probably filled by a long 

 narrow glacier discharging into Taylor or Dundas bay. Little 

 Avas known of the peninsula between Glacier bay and Lynn canal 

 before our expedition mapped its northern part, except that it is 

 entirely made up of glacier-bearing mountains, whose peaks are 

 from 5,000 to 7,000 feet high. 



Northwest of Cross sound the character of the coast changes 

 abruptly ; the coast line becomes continuous, without outlying 

 islands, and broken by few inlets ; and mountains of great height 

 rise immediately from the water's edge. We can, therefore, topo- 

 graphically divide the southeastern coast of Alaska into two 

 regions. The line between them passes along Cross sound ; then 

 follows the valley just northeast of the Fairweather range for 40 

 or 50 miles, beyond which point we know nothing whatever 

 about it. This topographic difference seems to be accompanied 

 by a geologic difference. Mr Russell has shown that the St. 

 Elias alps are of Tertiary origin ; * and probably the Fairweather 

 group belongs to the same range, though I believe it has not 

 been explored. If this is true, the Fairweather mountains are of 

 Tertiary origin, while the rocks forming the mountains about 

 Muir glacier, and probably the rest of the same topographic region 

 toward the southeast, belong to the Paleozoic and Archean.f 

 Another difference is quite marked. Mr Russell has found raised 



* Nat. Geog. Mag., vol. ill, 1891, p. 172. 

 fSee Supplements I and II. 



