NAVIGABILITY OF ALASKAN RIVERS. L25 



been much higher. At the time of our visit it was rapidly falling. The 

 return trip to Fort Yukon was made in about eighteen hours. 



The " Yukon " did not pass the mouth of Pelly river, as that was her des- 

 tination. She might easily have done so, however, had it been desirable. 

 She could have ascended the Yukon to and beyond the mouth of the Lewes, 

 and could also have ascended the Lewes as far as White Horse rapids, just 

 below Miles canon. The only place below White Horse rapids which seems 

 to offer special difficulty is at Rink rapids (Five Fingers), where the river is 

 obstructed by islands and the current is very swift. 



Above Miles canon the river is navigable for small steamboats all the way 

 to lakes Tagish and Bennett. The grand scenery of the numerous lakes 

 drained by the Lewes would attract many tourists should steamboats be 

 placed on them. 



The Tundra. 



geology of the treeless, moss-covered shores of alaska. 



Definition. — The name " Tundra " is used in Siberia to designate the vast, 

 treeless, moss-covered plains bordering the Arctic ocean and has been 

 adopted for the similar regions fringing the northern shores of North America. 



A general knowledge of Alaska derived from many sources* renders it 

 evident that the tundra occurs all along the borders of Behring sea and the 

 Arctic ocean. My observations concerning it were limited to the region 

 about St. Michaels, to the delta of the Yukon; and to the less typical shores of 

 Unalaska. 



General Characters. — The tundra in typical localities is a swampy, moder- 

 ately level country, covered with mosses, lichens, and a great number of small 

 but exceedingly beautiful flowering plants, together with a few ferns. The 

 soil beneath the luxuriant carpet of dense vegetation is a dark humus, and 

 at a depth exceeding about a foot is always frozen. On its surface there are 

 many lakelets and ponds surrounded by banks of moss even more luxuriant 

 than on the general surface. It is not always a level plain, however, but is 

 frequently undulating and may surround and completely cover hills of con- 

 siderable elevation. The dense tundra vegetation also extends up the 

 mountain side aud occupies the entire region where the conditions are favor- 

 able for its formation. At the localities where I examined it the whole 

 surface, excepting the faces of steep cliffs and thesummits of high mountains, 

 was covered with the same dense brown and green carpet. 



About the shores of Unalaska and for fully 2,000 feet up its rugged 



*The tundra of Alaska have been graphically described by the following writers : 



John Muir- Botanical Notes on Alaska; m Cruise oi tin- Revenue Steamer Corwin m Alaska and 

 the N W. Arctic ocean in 1881. Treasury Department, Washington, 1883, pp. I. 



0. L. Hooper: Report of the Cruise of the U. S. Revenue Steamer Ihomas Corwin in the Arctic 

 Ocean. 1881. Treasury Department, Washington, 1884, p. 35. 



L. M. Turner: Contributions to the Natural History of Alaska. Signal Office, Washington 

 pp. 15-16." 



