Summer Birt)0 of 3flatbea& Xahe 



p. M. SiLLOWAY. 



Notes based upon observations made between June 14 and 

 August 30, 1900. From June 14 to July 6, observations were 

 made from the University of Montana Biological Station at 

 the head of Flathead Lake as a center; from July 9 to July 

 18, at Sin-yale-a-min Lake, Mission Mountains; from July 19 

 to July 27, at McDonald Lake, Mission Mountains; from 

 July 28 to August 3, in the region between the foot of Mt. 

 McDonald and the foot of Flathead Lake; during the re- 

 mainder of the period stated, the Biological Station was again 

 the center of operations. 



Additional observations were made in June and July, 1901, 

 which have been recorded in the appropriate places. 



Prepared under direction of the University of Montana 

 Biological Station. 



SIN-YALE-A-MIN LAKE. 



Sin-yale-a-min Lake lies in a depression of the Mission 

 Mountains at an elevation of 3900 feet. The depression is 

 probably the result of glacial action, in which the bed of the 

 lake was scooped out by the moving ice-mass, the trend being 

 nearly from east to west. The western end of the depression 

 is blocked by what seems to be a terminal moraine, through 

 which the outlet of the lake makes its way. The lake is fed 

 by a stream which comes dashing down a gorge on the north- 

 east, the descent being so steep about a quarter of a mile from 

 the lake that there is a succession of beautiful falls extending 

 over several hundred feet. Between the lake and the falls the 

 stream is thickly bordered by massive arbor vitae, whose nu- 

 merous standing trunks and accompanying fallen growth form 

 an almost impassable jungle. However, a trail can be followeil 

 from the lake to the falls with no great difficulty. Along this 

 stream the cheerful chant of the winter wreti can be heard, 

 and in the leaping spray of the falls the American dipper 

 loves to play. 



