UPPER TENNESSEE DRAINAGE. 535 



Simpson, '14, pp. 754, 755, 790, 791. — Fusconaia barnesiana Ort- 



mann, '17, p. 59. 



Simpson, '14, p. 754, makes teUicocnse a synonym of barncsianum, 

 and (p. 755) lyoni a synonym of pudicnm. 



U. piidicns is practically the same as barncsianns, but with dis- 

 tinct rays; mcrcdithi is a pndiciis with only few rays; U. lyoni is 

 large and has rays ; it also has somewhat elevated beaks, inclining 

 thus toward the var. tumescens; tellicocnsis and Icnticularis are mod- 

 erately large, with indistinct rays, practically identical with bar- 

 nesianus. 



This form, which we must regard as the typical species, unfor- 

 tunately represents the intermediate condition between the flat and 

 swollen extremes. It is represented by shells from the Powell, 

 Clinch, and Holston, going up here well toward the headwaters ; in 

 Powell to Big Stone Gap, Wise Co., \^a. ; in the Clinch to Richland, 

 Tazewell Co., Va. ; in the Holston to the North Fork at Holston, 

 Washington Co., Va., and to the South Fork at Bluff City, Sullivan 

 Co., Tenn. In the downstream direction, it can be traced to the 

 Tennessee River below Knoxville. However, it is most abundant in 

 lower Powell, in the middle Clinch, and in the Holston near the 

 Forks. In addition, it turns up in many tributaries ; Cove Creek, 

 Campbell Co., Tenn. ; Coal Creek, Anderson Co., Tenn. ; Big Flat 

 Creek, Knox Co. ; in Little Pigeon River, Boyd Creek, Pistol Creek, 

 Tellico River, Cane Creek (McMinn Co.), Hiwassee River, etc. 



It is a common form, of rather universal distribution under the 

 proper conditions. Toward the headwaters, it passes generally into 

 the var. bigbycnsis, but there are some small creeks where this is 

 not the case (at any rate, where the bigbcnsis-iorm has not been 

 found). In the larger rivers it gradually passes into the form 

 tumescens, and is often found associated with it. 



Type locality: Cumberland River, Tenn. (not found by Wilson 

 and Clark, '14, although they mention " Flcnrobema crudum" 

 = barnesiana tumescens; the latter, however, surely has been mis- 

 identified). 



