PART I CHAZYAN AND RELATED BRACHIOPODS—-COOPER 473 
shallow, extending from umbo to anterior margin; flanks bounding sulcus swol- 
len ; lateral and posterolateral slopes long and steep. Notothyrial cavity of mod- 
erate size; brachiophore plates somewhat reclining ; median ridge short; pallial 
marks fairly well impressed. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
MEINE Fetes eis shai otis isd Shaw blo'dig ace 18.8 18.7 21.4 15.2 II.0 
Hypotype: .(1ty7oagoa)»). ra) dite. . 2. .aak 25.5 24.3 30.4 24.4 15.5 
rh CPEOBSGD YE Rain scabs says: Fesran 25 22.9 21.5 24.9 18.8 57,3 
MY CHRO NP osetia ou oak 18.2 18.2 20.0 15.6 10.9 
a CUERO Senne cs See dae ea 19.0 18.6 23.5 21.0 12.1 
Holotype (M. melonica M.C.Z. 8596).. 25.4 25.7 29.9 21.0 15.5 
Types.—Holotype: M.C.Z. 8609; figured hypotypes: 110680, 110686a,b, 
I10713a, 110715, 110718, 110752, 117038b, 117040c,d,f,i, 117041a,b, 117042b; 
unfigured hypotypes: 117038a, 117040a. Holotype Mimella melonica (Willard) : 
M.C.Z. 8596; holotype M. superba Butts: U.S.N.M. 98210. 
Horizon and locality —Benholt formation in Virginia: West slope of the hill 
% mile east of Cedar Point School, Hilton (T.V.A. 197-NW) Quadrangle; 
south side of Mount Hagan School, Hilton (T.V.A. 197-NW) Quadrangle; 
roadside 4 mile southwest of New Bethel Church, Hilton (T.V.A. 197-NW) 
Quadrangle; $ mile northeast of Speers Ferry, Clinchport (T.V.A. 188-NW) 
Quadrangle; Fugates Hill, 2 miles N. 45° W. of Mendota, Bristol (30’) Quad- 
rangle; Lake View Church on Virginia Highway 71, Russell County; Virginia 
State Highway 80, $ mile south of Rockdell, Elk Garden (T.V.A. 212-NW) 
Quadrangle; on the road to Hansonville, 4 miles northeast of Gate City, Gate 
City (T.V.A. 188-NE) Quadrangle. 
Benbolt formation Tennessee: 0.1 to 0.2 mile north of the road 1.1 miles north- 
east of Lee Valley, Lee Valley (T.V.A. 171-NW) Quadrangle. 
Ridley formation in Georgia: On U. S. Highway 27, just northwest of Chicka- 
mauga Creek, Kensington (T.V.A. 106-SE) Quadrangle. 
Dryden formation in Tennessee: Lone Mountain to Tazewell road, 14 miles 
northeast of Lone Mountain, Tazewell (T.V.A. 154-NE) Quadrangle; hillside 
south of Dutch, Dutch Valley (T.V.A. 154-SE) Quadrangle; 2 miles northeast 
of Heiskell, Powell Station (T.V.A. 137-SE) Quadrangle; Sycamore Creek, 
northwest corner Maynardville (T.V.A. 145-SE) Quadrangle; south side of 
the road 1 mile northeast of the watergap south of Bray, Morristown (30’) 
Quadrangle. 
Dryden formation (Benbolt part) in Virginia: Several localities at Rye Cove, 
Clinchport (T.V.A. 188-NW) Quadrangle. 
Discussion.—This species is characterized by its large size, actually approach- 
ing that of M. imperator but never equalling it. Mimella globosa is further 
featured by its nearly rectimarginate anterior commissure. The commissure 
when folded has a broad and gentle wave in the direction of the brachial valve. 
This character is like that of the Chazyan Mimellas, but they are generally with 
stronger ornamentation than any of the Benbolt forms. The brachial valve of 
