BIOLOGICAL RECONNOISSANCE AT FLATHEAD LAKE. 123 



The Mission Valley. 



This beautiful valley is bordered by the Mission mountains on the 

 east, the Jocko river on the south, the Pend d'Oreille river on the west, 

 Flathead lake on the north. The extreme length is about 35 miles, the 

 extreme width about 15 miles. A terminal moraine separates the lake 

 from the valley, bordering the lake on the southern end. The country 

 immediately south of the moraine for a distance of ten miles is beautiful. 

 It is level land, rich, capable of making good farms, easily irrigated. A 

 large sand dune stretches across the valley about 15 miles from the lake, 

 extending east and west. The eastern end is free sand, is not yet held 

 in place by vegetation, and is slowly creeping eastward. The free and 

 movable sand is 12 to 15 feet high, clean looking and white. Some eight 

 or ten miles from this free sand westward one comes to the Pend d'Oreille 

 river. The country abounds with depressions and coulees, with several 

 large buttes trom 100 to 200 feet high. It is in this region that the 

 buffalo herd ranges. 



The valley is crossed by four large creeks, as follows: Mission creek 

 is the most southern. It takes its source in two canons, one the outlet of 

 Sinyaleamin lake, the other Mission creek proper, with its high 

 falls, visible for miles on the plain. Sinyaleamin lake receives 

 its water from the eastern slopes of the mountains, principally from Snow 

 lake, which is full of slush snow even in July. The stream leaving Snow 

 lake tumbles over a beautiful cascade just before it enters the lake. ThQ 

 lake is described elsewhere. The stream from this lake joins Mission 

 creek proper a short distance from St. Ignatius Mission. A third and 

 smaller branch emerges from the canon between Mission canon and Mc- 

 Donald lake. This branch takes its rise in two small and beautiful alpine 

 lakes. Twin lakes, lying high up in the mountains, fed by melting snows. 

 Except in early spring this water is consumed in irrigation. Mission creek 

 flows a little to the north of west, receiving Post creek a few miles west 

 of the Mission, finally flowing into the Pend d'Oreille river, Mission 

 creek may be located by examination of Plate XIX. Post creek is tha 

 outlet of McDonald lake, which receives most of its waters from the 

 slopes of McDonald peak. The creek forming the inlet of the lake has 

 two forks, one taking the waters from McDonald peak, the other from tha 

 peaks immediately to the north. This northern branch flows through 

 two small lakes, and has some beautiful cascades, seen plainly from Mc- 

 Donald peak. Neither of these branches is known save for a very short 

 distance from the lake. Post creek flows southwest into Mission creek 

 as previously mentioned. Crow creek takes its rise in the mountains 

 still farther to the north, in the canon through which runs the Crow creek 

 trail. This trail is the Indian route across the range to the Swan river 

 and Big Blackfoot river country. As it crosses the range at a high altitude 

 it is passable only in summer, and is the only passageway between tha 

 Jocko river and the northern end of the Mission range. The creek flows 

 a little south of west, receiving Mud creek near the sand dune previously 

 mentioned, and flowing into the Pend d'Oreille river. It is a large creek, 



