106 I. C. RUSSELL DRPACE GEOLOGY OF \I..\sK.\. 



the continuation of the Yukon and should share its name. It flows through 

 a continuation of the same orographic valley that is occupied by the Yukon 

 (or " Lewes " i below its mouth, while the Yukon (of the U. 8. Coast Survey 

 map) or the Lewes (of Dawson's map) above the junction is but a tributary 

 stream, coursing through a narrow and poorly defined valley nearly at right 

 angles to the main line of drainage. 



The fact that the so-called Tes-lin-too occupies a continuation of the Yukon 

 (Lewes) valley proper has been clearly recognized by Dawson, as is shown 

 by the following quotation : 



"The valley near the mouth of the Tes-lin-too is again narrower than usual, 

 Bingularly so for the point of confluence of two important rivers. The valley of the 

 Tes-lin-too is evidently the main orographic depression which continues that occupied 

 by the Lewes below the confluence. The Lewes flows in through a narrow gap, 

 closely bordered by high hills and nearly at right angles to the lower course of the 

 river. On the map accompanying Lieut. Schwatka's report, the width of the 

 Tes-lin-too is shown as about half that of the Lewes, the actual fact being precisely the 

 reverse and all the main features of the lower river being contained by the Tes-lin-too ; 

 while the ether branch, both in its irregular mode of entry, the nature of its banks, 

 the color of it- water and its very rapid current, presents, at first sight, all the 

 appearance of a tributary stream of new character. To such an extent is this differ- 

 ence ohservable, thai Mr. Ogilvie and the members of bis party, as well as most of the 

 miners on the river, were of the opinion that the Tes-lin-too actually carries much 

 the greater volume of water. As this appeared to be a question of some importance, 

 we -topped a day at the confluence for the purpose of investigating it, cross-section- 

 ing each river and ascertaining the rate of the current at distances of about half a 

 mile from the junction, where the circumstances were favorable. It was thus ascer- 

 tained that the rivers possess the following dimensions: — 



/.• iocs. '/'■ -I'm-too. 



Me : ,n width 420 feet. 575 feet. 



Maximum depth (near left bank). _ 12 " (near right hank) 18 feet 4 in. 



Sectional area 3,015 - ; 3,809 feet. 



Maximum velocity 5.68 miles pr. hr. 2.88 miles pr.hr. 



Discharge per second 18,664 cubic feet. 11,436 cubic feet. 



•• In connection with these measurements it may be stated that the Lewes showed 

 evidence of having risen about a foot above its lowest summer level, while the Tes- 

 lin-too was probably near its lowest summer stage. (All the rivers in this country 



reach their actual minimum toward tl nd of the winter.) I fwe Bubtrad the volume 



water represented by this extra foot in depth, the discharge ofthe Lewes at the 

 summer low-water .stage may be approximately stated at 15,600 cubic feet."* 



The secondary character of the stream draining Lake Lebarge where it 

 joins the " Tes-lin-too " is indicated by the fact thai a party of miners who 

 had descended from Lake Lindeman to Forty-mile creek, and tnighl there- 



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Yiik.,ii District, lOC. 'II., !•■ L53b. 



