1354 THE NAUTILUS. 
of many mussels and fish, which now no longer exist in the lower half of 
the Monongahela, 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, asmall 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 MeKees- 
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 Youghiogheny.* A similar condition exists 
in the Allegheny river above Pittsburg, as far asmy search extended 
a few miles above Sharpsburg, ouly 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. /igamentinus 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 mollusca at the lower end of Neville Island 
opposite Coraopolis, but without success, only a few cast-up shells of 
ligamentinus and crassidens being noted. Just as I had given up the 
search and was wuting fora trolley car on the bridge above Coraopolis, 
connecting the city with Neville Island, [ 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 sulphurie¢ 
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. 
