478 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Types.—Holotype: 1107094 ; figured paratypes: 110700a-d, 110702a, 110706b; 
unfigured paratypes: 110700e, 110702b-f, 110706a, 110709b. 
Horizon and locality—Lincolnshire formation in Tennessee: 4 mile northwest 
of Eidson Post Office, Kyles Ford (T.V.A. 170-SE) Quadrangle; Evans Ferry 
section, northeast of Indian Creek on U. S. Highway 25E, Howard Quarter 
(T.V.A. 162-NW) Quadrangle; on U. S. Highway 25E, Thorn Hill section, 
shale unit south of first bridge north of Thorn Hill Post Office, Avondale (T.V.A. 
162-SW) Quadrangle. 
Lincolnshire formation in Virginia: In Marcem Quarry, 2 miles west of Gate 
City, Gate City (T.V.A. 188-NE) Quadrangle; Virginia Highway 19, 0.3 mile 
east-southeast of Hansonville, Hansonville (T.V.A. 205-SW) Quadrangle; at 
spring + mile east of junction of Virginia Highways 608 and 652, 6 miles south- 
east of Staunton, Augusta County; north side of Moccasin Creek, 0.2 mile west 
of New Bethel Church, Hilton (T.V.A. 197-NW) Quadrangle. 
Murat formation (calcarenite facies of Lincolnshire) in Virginia: 2 miles 
northwest of Lexington, Lexington (15’) Quadrangle. 
Discussion—This is not a common species as far as the author’s collecting 
experience in the Appalachians indicates. It was common in the shaly beds of 
the Lincolnshire formation north of Eidson, but that place is now fairly well ex- 
hausted. The species, as usual with Mimella, is somewhat variable in all its 
features. Generally it is rectangular in outline with a fairly wide hinge, mod- 
erately inflated valves, usually moderately uniplicate anterior commissure, promi- 
nent beak, and moderately strong costellae. 
This is one of the largest of the Mimella species below the Benbolt and, inas- 
much as it occurs in some shaly beds, it may be confused with M. globosa. It, 
however, seldom attains the large size of that species and usually has more pro- 
nounced anterior folding and finer costellae than the Benbolt form. The Lin- 
colnshire species differs from M. intermedia in its more transverse outline. It 
differs from M. twmida of the Hogskin member in its generally smaller size, finer 
ornamentation, and more quadrate form. 
Specimens from the Lincolnshire formation at Marcem Quarry west of Gate 
City have been placed here, although they are larger and with somewhat more 
inflated pedicle valve than M. laticardinia, but medium-sized specimens from 
the same place are very close to the Eidson forms. 
MIMELLA LATISTRIATA (Wilson) 
Hebertella latistriata Witson, Trans. Roy. Soc. Canada, ser. 3, vol. 26, sec. 4, p. 380, pl. 2, 
figs. 4-7, 1932. 
Types.—Holotype: G.S.C. 6524; paratypes: G.S.C. 6524a, 6525. 
Horizon and locality.—Aylmer formation in Ontario, Canada: From the shaft 
at the west end of Barnhart Island southwest of Cornwall. 
