382 



/. T. PARDEE 



In order to understand the problem of the locality of the dam it is 

 necessary to glance briefly at the topography of northwestern Montana 

 and the adjacent panhandle of Idaho. From the map (Fig. 4) it 

 appears that that portion of Montana west of the continental divide 



Fig. 4. — Map of northwestern Montana and adjacent portions of Idaho com- 

 piled from the U. S. General Land Office maps of Idaho and Montana, topographic 

 sheets of the U. S. Geological Survey, etc. 



is largely occupied by an irregular depression, drained by Clark Fork 

 of the Columbia River. If this depression were filled with water to 

 the 4,200-foot contour, the lake formed would be effectively imprisoned 

 on the east and south by the main divide and on the southwest by the 

 Bitter Root and Coeur d'Alene mountains, but to the northwest no 



