110 DESTRUCTION OF FRESH-WATER FAUNA. [April 23, 



would improve conditions considerably. The presence of dams in 

 our rivers or creeks furnishes, to a certain degree, the conditions 

 required for such clearing basins, and we have observed instances 

 (Mahoning River at Edinburg, Lawrence County), where such a 

 dam actually improves the river to a considerable degree. This is 

 also the case, although not so strikingly, with dam No. 6 in the Ohio 

 River. But the trouble is these dams improve the water after much 

 damage has been done already, and are injurious in other respects 

 (see above). 



This much, however, should be clear — unless we improve the 

 quality of the water of our rivers, it is impossible to bring back the 

 original condition of their fauna, and attempts to restore our nat- 

 ural resources with regard to the fish fauna, by restocking our pol- 

 luted streams with fish, will be labor and money thrown away. 



Carnegie Museum, 

 Pittsburgh, Pa. 



