134 THE NAUTILUS. 



of many mussels and fish, which now no longer exist in the lower half of 

 the MoDongahela,if the waters had their free course ; but the damming 

 of the river has so concentrated this sewage during low water that the 

 imprisoned animals have no relief from the free flow of the current nor 

 means of escape from the limits of the dammed area. The Mononga- 

 hela is said to be now dammed for purposes of navigation throughout 

 its entire length in Pennsylvania and for some distance farther into 

 West Virginia. Old rivermen told me that it was useless to try and 

 get live mussels below Cheat river, though only a year since, a small col 

 lection of uniones from the Monongahela near Charleroi, Washington 

 county, was made for the Carnegie Museum. It is noteworthy, how- 

 ever, that most, if not all, of these were " dead " shells. At McKees- 

 port, the junction city of the Monongahela and Youghiogheny rivers, I 

 was unable to find any evidences of molluscan life in the waters of 

 either river, nor were any dead shells to be found on the mud banks 

 and shoals exposed by the very low stage of water then prevailing. A 

 boatman stated that there was little hope of finding any live mussels 

 below Connellsville on the Yousjhiogheny.* A similar condition exists 

 in the Allegheny river above Pittsburg, as far as my search extended 

 a few miles above Sharpsburg, only dead shells of the larger uniones 

 being found where three years since a member of the High School 

 Naturalists' Club of Pittsburg told me he had secured the living animals- 

 The same remarks apply to Chartier's creek within the city limits and 

 flowing into the Ohio river at McKees rocks, just above the Davis Island 

 dam. A few dead shells of U. Ugnmcnthuis were picked up in the bed 

 of this creek. Following the instructions of Mr George H. Clapp, of 

 Edgeworth, Allegheny county, Pa., who kindly gave me the full benefit 

 of his intimate knowledge of the Ohio river between his home and Pitts- 

 burg, I searched for water niollusca at the lower end of Neville Island 

 opposite Coraopolis, but without success, only a few cast-up shells of 

 liyamentinus and crassidens being noted. Just as I had given up the 

 search and was wilting for a trolley car on the bridge above Coraopolis, 

 connecting the citj with Neville Island, I espied some live uniones in the 

 shallow running water of the "back river" which flows beneath the 



* This is, no doubt, largely due to the immense volume of " mine water " now 

 discharged Into the river. This " mine water " is heavily charged with sulphuric 

 acid, due to the leaching out of the sulphate of iron in the coal measures. At 

 times of excessively low water the percentage of free acid in the water is so high 

 that works along the banks of the Youghiogheny and Monongahela rivers as far 

 down as Pittsburg have been forced to suspend operations, due to the eating out 

 of the steam boilers, and the railroads which use this water in their engines, for 

 lack of a better supply, have spent large sums of money in putting up treating 

 tanks in which to neutralize the acid before pumping into the boilers. G. H. C. 



