THE PHYSIOGRAPHY OF THE FLATHEAD LAKE REGION. 197 



The Physiography of the Flathead Lake Region. 



Mortan John Elrod. 



The first thing one must do in a new locality is to become familiar 

 with 'the lay of the land.' The surface geography and geology of a re- 

 gion must first be understood if one is to seriously discuss the botanical 

 or zoological life. The character of the soil determines to a large extent 

 the general character of the vegetation, and the surface irregularities 

 will indicate the nature of the zoological life. In a region where roads, 

 fences, houses, and similar works of man are absent, a knowledge of the 

 country is all the more important in order to get aver the country. Since 

 much of the country is as yet unexplored the physiography of the region 

 will be especially interesting to those working at the station. 



The views here given are based on the observations of the past four 

 years. Later study may require that they be modified in part, but it is 

 believed the observations will aid very much in working out the exact 

 changes that have taken place in this section of the state. The glacia- 

 tion of the region offers a good field for detailed work. 



The Mission and Swan ranges of mountains, in northwestern Mon- 

 tana, lie parallel with each other, extending north and south in general 

 direction. The Mission range is about seventy-five miles long, ending 

 as a range at the Biological Station. The Swan range extends twenty- 

 five or thirty miles farther north. Both ranges were made by faulting. 

 The stronger throw v/as at the southern end of the ranges, where the 

 high peaks, reaching 10,000 feet, are found. Between the two ranges the 

 Swan river flows toward the north. It enters Swan lake, still between 

 the ranges, far down the side. From Swan lake the river flows still 

 northward for a few miles, then winds around with a big bend and turns 

 westward through a new channel to its inlet into Flathead lake. That 

 portion of the Swan range which extends north of the Mission range 

 borders directly on the valley north of Flathead lake, rising abruptly from 

 the plain, without foothills. 



The formation of the ranges gave to the western side of each an abrupt 

 and steep face, intersected with many ravines and canyons, with more 

 gradual slopes on the eastern sides. The western base of the upper end 

 of the Mission range is washed by Flathead lake, which for the greater 

 portion of the distance meets the mountains with abruptness. There is 

 little level or tillable land between, and often scarcely room for a wagon 

 road. 



South of Flathead lake a large valley, Mission valley, extends soutli- 

 ward for thirty-five miles. North of the lake is another large valley 

 which continues northward to the British boundary. On the western 

 shore a spur range of the Kootenais shuts in the waters of the lake. The 

 outlet of the lake is through a new channel, with a series of rapids, a 



