UPPER TENNESSEE DRAINAGE. 525 



exchanges of rare forms. As has been mentioned above, also Walk- 

 er's collection has been examined, and incidentally some of the ma- 

 terial of the U. S. National Museum, in Washington, chiefly some 

 of Lea's types, has been studied. 



It is believed that the Carnegie [Museum possesses now the best 

 collection representing the Upper Tennessee fauna, and with regard 

 to the illustration of the distribution of the various forms, it has no 

 equal, not to speak of the fine collection of soft parts. In view of 

 the gradual, slow but steady, deterioration of the fauna in conse- 

 quence of stream-pollution, there is great danger that the fauna will 

 largely become destroyed, and that it will be impossible, in the future, 

 to duplicate this collection. At the present time, conditions are fair, 

 in some parts splendid; but there are already polluted streams, in 

 which the fauna is gone. Such are : the Powell River, for a certain 

 distance below Big Stone Gap, Va. (wood extracting plant) ; the 

 North Fork Holston for a distance below Saltville, Va. (salt and 

 plaster of Paris industries) ; French Broad River at Asheville, N. 

 Car. (pollution comes — as I have been informed — from Davidson 

 River, farther up) ; Big Pigeon River, from Canton, N. Car., all the 

 way down (woodpulp and paper mill) ; Tellico River below Tellico 

 Plains, Tenn. (old wood pulp and extracting mill). The building 

 of dams (for water power, etc., for instance in Nolichucky River 

 near Greenville, Tenn.) also has a deteriorating effect upon mussel 

 life, and all this surely will increase in the future. 



Bibliography. 



Aside from the well-known older papers of Lamarck, Say, Rafinesque, 

 Conrad, Call, and others, the following have been principally used in the 

 preparation of this paper. 



Frierson, L. S. 



191 1. Remarks on Uiiio varicosus, cicatricosus and Unio compertus new 



species. Nautilus, 25, 1911, pp. 51-54. 

 1914a. Remarks on Classification of the Unionidse. Nautilus, 28, 1914, 



pp. 6-8. 

 1914&. Observations on the Genus Symphynota. Nautilus, 28, 1914, p. 40. 

 Goodrich, C. 



1913. Spring Collecting in Northwestern Virginia. Nautilus, 27, 1913, 

 pp. 81, 82; 91-95. 

 Hinkley, A. A. 



1906. Some Shells of Mississippi and Alabama. Unionidae. Nautilus, 

 20, 1906, pp. 52-55- 



