BIOLOGICAL, RECONNOISSANCE AT FLATHEAD LAKE. 153 



Echo Lake. 



This interesting lake lies close to the Swan range of the Kootenai 

 mountains, between the Swan range and Flathead river. It is but eight 

 or nine miles from the Biological Station. 



The outline of the lake is very irregular. From the mountain tops 

 the outline very much resembles the letter H, with small projections in. 

 different directions. This may be studied from examination of Plate 

 XXX\T:I. The total shore line of the lake, including all the arms, is said 

 to be from 12 to 14 miles. The width varies from a half mile to a narrow 

 neck. 



Its depth is said to be great at the eastern arm, the head of the lake, 

 but the soundings showed less than 20 feet. 



The lake has no surface outlet. The waters are held in by glacial 

 deposit, evidently a portion of a moraine. The waters escape through 

 an underground outlet, finally reaching Flathead river, though just where 

 the outlet is or how far it extends underground is not yet known. 



Very recent, or present connection with some large body of water is 

 indicated by the presence of at least four species of fish, the squawfish, 

 Ptychocheilus oregonensis, Rich., whitefish, Corregonus williamsoni, 

 Girard, minnow, Leuciscus, probably gilli, and trout, Salmo mykiss. It is 

 said to have suckers, Catostomus, also. A very large spring is reported 

 a short distance from the lake on the west, but it has not yet been ex- 

 amined. 



The lake has an annual rise of from five to seven feet, the waters fill- 

 ing up with the melting of snow in the spring and summer, reaching the 

 low stage again late in the fall or early in the winter. The drainage is 

 from a small portion of the west slope of the Swan range, and a small 

 portion of the timbered valley adjacent to the waters of the lake. 



The lake lies in a trough or depression in the wooded valley. Its 

 banks are steep slopes, leading up to the valley plain, densely wooded 

 with fir, tamarack, lodgepole pine, yellow pine, and an occasional white 

 pine. Maple, alder, cottonwood and birch are present, but less numerous. 



In the year 1894 the surface of the lake rose during the freshet to a 

 point some ten or twelve feet above its usual height, and has remained 

 so ever since. This elevation of water surface, and consequent sub- 

 mergence of land, appears to be due not to the submergence by sinking 

 of land surface, but to filling up the underground outlet, preventing the 

 water from escaping. This additional depth of water has drowned con- 

 siderable vegetation, find in one case has submerged a meadow of sev- 

 eral acres, including house, barn, and fences, the lake water covering 

 to a depth of several feet what was formerly a meadow and garden. The 

 old house at present has the water half way up the door, whereas pre- 

 vious to the rise it was on the bank of a creek emptying into the lake. 

 What was formerly the mouth of the creek, and for a quarter of a mile 

 back, is now a part of the lake. This is plainly shown in Plate XLII. 

 The bridge in the illustration formerly spanned the creek. The water 

 is new lake. 



This photograph was taken during the summer of 1901. In 1902 a 



