UPPER TENNESSEE DRAINAGE. 561 
Chilhowie, Smyth Co., Va.; South Fork Holston River, Barron, 
Washington Co., Va.; Big Creek (tributary to Holston), Rogerville, 
Hawkins Co., Tenn. (Walker coll.) ; Little Pigeon River, Sevier- 
ville, Sevier Co., Tenn.; Boyd Creek, Boyd Creek, Sevier Co., Tenn. ; 
Little River, Melrose, Blount Co., Tenn.; Pistol Creek, Rockford, 
Blount Co., Tenn.; Conasauga Creek, Monroe Co., Tenn. (Walker 
coll.) ; South Chickamauga Creek, Ringgold, Catoosa Co., Ga. 
Type locality: Tennessee (and “ North Carolina,’ but no exact 
locality given). 
41. ALASMIDONTA (DECURAMBIS) MARGINATA (Say), 1819. 
Alasmodonta marginata Say, ’19.—Margaritana marginata Lewis, 
*71—Alasmodonta marginata Pilsbry & Rhoads, ’96.—Alasmi- 
donta marginata Ortmann, ’12), p. 297 (anatomy ).—Alasmidonta 
marginata Ortmann, 7130, p. 311—Alasmidonta marginata Good- 
rich, 713, p. 94.—Alasmidonta (Rugtfera) marginata Simpson, 
14a Ds SOA: 
As to the subgenus Decurambis Raf., ’31, see Frierson, ’14a, p. 7. 
Generally distributed over the whole upper Tennessee region, but 
apparently more abundant toward the headwaters. Goes, in the 
Powell, to Olinger, Lee Co., Va.; in the Clinch, to Richland, Taze- 
well Co., Va.; in the Forks of the Holston, to Saltville and Chilhowie, 
Smyth Co., Va., and is also in Big Mocassin Creek, Scott Co., Va. 
Pilsbry & Rhoads report it from Watauga River at Johnson City, 
Washington Co., Tenn. It is also in Ocoee River, at Ducktown, Polk 
Co., Tenn. (Walker coll.). 
Type locality: Scioto River, Chillicothe, Ohio. 
42. ALASMIDONTA (DECURAMBIS) RAVENELIANA (Lea), 1834. 
Margaritana raveneliana Lea, ’34.—Alasmidonta (Rugifera) ravene- 
liana Simpson, 14, p. 507. 
Differs from A. marginata chiefly in the absence of rugosities on 
the posterior slope. However, in very young specimens, traces of 
them are sometimes seen, so that this characteristic feature of the 
subgenus Decurambis (Rugifera) is still indicated. This form un- 
doubtedly is an offshoot of the marginata-stock, separated from the 
