334 RECORDS. 



June 5, and remained until June ii, waiting for the ice to 

 break up in the Yukon River. On June 1 1 , the route was by 

 railroad to Whitehorse, Yukon Territory; June 12-15, by 

 steamboat down the upper waters of the Yukon to Dawson, 

 Yukon Territory, where a nineteen-foot Peterboro' canoe was 

 purchased and the trip down the river begun. The trip was 

 ended at Anvik, Alaska, August 12, after about 1,100 miles of 

 the river had been explored, and about 1,800 lbs. of specimens 

 had been collected and shipped. The highest point north was 

 reached at Fort Yukon, July 2, just beyond the Arctic Circle. 



The Yukon River occupies what was until quite recently a 

 broad estuary. Subsequent elevation of the land resulted in the 

 draining of the estuary and the formation of the present river 

 valley, which has cut its way down through the estuary de- 

 posits, leaving these as broad benches or terraces. Mastodon 

 and other remains of extinct animals indicate the Pleistocene 

 age of the deposits. One of the finest exposures is at the 

 ■*' Palisades," just below Rampart. 



The width of the river varies from one to ten miles, and the 

 main channel is constantly shifting. It pursues a meandering 

 course, sometimes impigning on the side ol the old valley, 

 sometimes on the other, and for long distances flows through the 

 middle. Where it occupies the latter position, it is generally 

 broad, with a current of about four miles per hour, and filled 

 with innumerable wooded islands, mud flats and sand and gi'avel 

 bars, which render navigation more or less a matter of guess- 

 work, on account of the impossibility of telling where the main 

 channel flows, and the liability of running into a blind slue or a 

 long circuitous channel around an island. It was often found 

 advisable to climb up the river bank to a considerable elevation 

 in order to determine, by means of an extended view, where the 

 correct course lay. Where hard rocks were exposed along the 

 river banks, or a short distance away, these were subjected to 

 careful examination in regard to their lithologic, pala^ontologic 

 and stratigraphic characters. 



Amongst the interesting results obtained were (i) the deter- 

 mination of the Tertiary age of certain sandstones above Ram- 



