10 BOTANICAL SURVEY OF THE CCEUR d'aLENE MOUNTAEVS. 



been determined. As before remarked, they are strictly nonfossilifer- 

 ous. Judging from this fact and taking into consideration their highly 

 metalliferous character, as well as the position, extent, contents, and 

 general appearance of the mineral-bearing lodes which traverse them, 

 I am inclined to place them among the pre Cambrian rocks of the 

 continent. 



DRAINAGE. 



The drainage system of the Coeur d'Alene basins is composed of two 

 principal water courses, which divide and subdivide over and over again 

 and form that most intricate system of lateral streams, some of then of 

 considerable size, which is such a prominent feature of the region. 



The primary water courses are the Coeur d'Alene and St. Joseph 

 rivers. The waters of these streams flow into Lake Coeur d'Alene, 

 which is thus in a measure a large storage reservoir for the entire drain- 

 age from all the interior basins. 



The Cceur d'Alene River empties into Lake Coeur d'Alene about 32 

 kilometers (1*0 miles) south from the north end of the lake. At a dis- 

 tance of 05 kilometers (40 miles) above its outlet it divides into two 

 streams, the North and South forks of the C<eur d'Alene River. The 

 North Fork, which is the larger stream of the two, heads in the moun- 

 tains near the north end of Lake Pend Oreille. It flows in an inclosed 

 triangular basin, a repetition on a small scale of the greater Coeur 

 d'Alene triangle. It is very tortuous, and its course on the whole lies 

 near to the eastern side of the triangle; that is, to the main range of the 

 Bitter Roots. Its exact length is unknown, but probably is about 175 

 kilometers (or nearly 110 miles). The elevation of the valley is about 

 1,200 meters (3,000 feet) in the upper portion and 070 meters (2,200 feet) 

 at its junction with the South Fork. Near the town of Kingston it 

 breaks through the basal ridge of its basin ami effects a junction with 

 the South Fork. It has here a width of about 70 meters (2.'50 feet) and 

 a mean summer stage of water I meter (.'5.3 feet) in depth. Tito South 

 Fork heads in the ridges of the Litter Roots a few kilometers to the 

 north of Sohons Pass. Its basin is a rectangular area, its long diame- 

 ter stretching east-southeast. From its junction with the North Fork 

 to its head in the Litter Roots is a distance of about 65 kilometers (-40 

 miles). The elevation of its valley at the upper end is about 1,000 

 meters (3,478 feet) and at its junction with the North Fork about G70 

 meters (2,200 feet). At the point of junction its width is ,'50 meters (98 

 feet), with a summer stage of water of about 75 centimeters (2.5 feet). 



In this report, unless especially stated to the contrary, whenever the 

 North Pork or the South Fork is mentioned the respective fork of the 

 Cumr d'Alene River is invariably meant. 



The Coeur d'AleneRiver is navigable in high water from the junction 

 of its two forks to its outlet into Coeur d'Alene Lake, a distance of 

 about (55 kilometers (40 miles). The summer and fall stages of water 

 do not permit navigation farther than to the old Coeur d'Alene Mission. 



