LIVINGSTON RANGE 313 



extensively mantled with snow and carries a small glacier on its north- 

 eastern slope. This is the southernmost peak of the Livingston range, 

 from which the crest is extended northwestward to its limit, probably in 

 mount Head, in British Columbia, about in latitude 50 degrees 25 min, 

 utes. Like the Lewis crest, that of the Livingston range is often narrow- 

 but of the two it is the wider, and it presents massive mountain groups* 

 with pyramidal forms instead of knife-edge arettes. Between these 

 groups are deep U-shaped wind gaps, very similar to those which mark 

 the Lewis range, and from them the descents are steep to the headwaters 

 of streams flowing southwesterly. 



The main continental divide from a point in British Columbia follows 

 the Livingston range to latitude 48 degrees 50 minutes, not quite as far 

 south as mount Heavens, then descends on to Flattop mountain between 

 Little Kootna and McDonald creeks, and ascends to the Lewis range, 

 which it follows about to latitude 46 degrees 45 minutes. 



The western slope of the Livingston range is deeply sculptured by 

 valleys which, descending from the wind gaps, contain long, narrow lake 

 basins. Each one of the streams south of the 49th parallel — Kintla, 

 Bowman, Quartz, Logging, Camas, and McDonald — spreads out into one 

 or more lakes, which vary in length from 2 to 10 miles. Unlike the 

 rock-bound pools which lie in the amphitheaters of Lewis range, these 

 waters are margined chiefly by slopes of gravel or talus, and only about 

 their upper ends do the mountains rise with anything approaching a 

 precipitous character. The shores and slopes are forest-clad, giving them 

 an aspect very different from that of the valleys on the northeastern side 

 of the mountains. 



Although the mass of the Livingston range is thus deeply sculptured, 

 the limit of the mountains on the west is definite, and, unlike the sinu- 

 ous margin of the Lewis range toward the Great plains, it has the char- 

 acter of a bold face rising from foothills. 



FLATHEAD VALLEY 



West of the Livingston range in the United States and southern British 

 Columbia extends the valley of the North fork of Flathead river. It is 

 a broad depression with a general altitude along the river course from 

 3,100 feet near the forks of the Flathead to 3,500 feet about the 49th 

 parallel. The river is a swift, clear stream, sometimes 50 yards wide, 

 with many gravelly bars and deep pools. It winds in numerous ox- 

 bows, now between low gravel banks of its flood plain, again past higher 

 terraces of drift, and occasionally under bluffs of stratified clays, with 

 which sandstones and lignites are interbedded. The wide valley opens 



XL VII— Bull. Geol. Soc. Am., Vol. 13, 1901 



