120 



ALASKA FISHERIES AND FUR INDtTSTRIES IN 1919. 



basin, and confined so closely by the Chugach Mountains that the 

 streams tributary to it are short and turbulent, often blocked by 

 impassable falls within a short distance of the point where they join 

 the main river. Furthermore, in the 70-milc stretch from the mouth 

 of the Chitina to the delta, the Tickel and the Tasnuna from the west 

 and the Bremner from the east are the only streams of any particular 

 size. These factors have an important bearing upon the question of 

 the spawning places of the salmon. 



Coi)por River Valley. 



The Copper River itself is heavily silt laden, and its waters nowhere 

 and at no time during the period of migration are clear enough to 

 afford a view of the fish, except where the salmon break the surface 

 in their movements. During its course through the plateau it is more 

 or less spread out in numerous channels intercepted by sand bars 

 and islands, and even through the mountains the same characteris- 

 tics manifest themselves wherever the steep, rocky slopes on the east 

 and west are sufficiently separated from each other to afford any 

 opportunity for the deposit of a sand-and-silt i)lain. While short 



