PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 283 
scar located in the posterolateral extremities. Shell substance impunctate, 
corneous. 
Genotype—Eoconulus rectangulatus Cooper, new species. 
Discussion.—This peculiar little shell occurs in abundance in the residues from 
the acetic acid etching of the Pratt Ferry limestone. The specimens are usually 
without an apex, which must have been easily exploded by the carbon dioxide 
resulting from the etching. At present the pedicle valve, which was undoubtedly 
attached, is not known. The genus occurs in the Pratt Ferry limestone and in 
the basal beds of the Botetourt formation in Virginia. 
This genus differs from Petrocrania in its impunctate and “chitinophosphatic”’ 
shell and the simplicity of its interior. It is undoubtedly an early form of the 
Craniidae but occurs with undescribed normal examples of Petrocania. 
EOCONULUS RECTANGULATUS Cooper, new species 
Plate 10, B, figures 11-13 
Shell small to minute with the posterior margin nearly straight and slightly 
wider than the anterior margin; sides nearly straight to strongly rounded ; antero- 
lateral and posterolateral extremities narrowly rounded. Anterior and posterior 
slopes subequally steep ; apex slightly eccentric. 
Measurements in mm.— 
Length Width Height 
SUMTER RS aoc Biotest spa ote cucaneaeetaee I.I 1.4 0.5 
Paratype CLIOGSAOD) ites sccissue cis tielere etn elelsre ctor i 1.6 0.9 
ns (CHTIOSAGENE!. 8% eee eee cincboue eens 2 1.4 0.8 
d (@rb84od) eee as. JS Baa see 1.4 2.0 1.2 
rs (iGSAGe): GHIssiss: ¢sch skies Dheao ae 1.4 2.1 0.8 
Types.—Holotype : 1168402 ; figured paratype: 116840b; unfigured paratypes: 
116840c-e. 
Horizon and locality.—Pratt Ferry formation in Alabama: 0.2 mile southeast 
of Pratt Ferry, Blocton (15’) Quadrangle. 
Discussion.—Another species occurs in the Botetourt limestone of Virginia on 
the south side of the road 0.2 mile east of Strasburg Junction. This is a large 
species differently shaped from E. rectangulatus, but the specimens are not good 
enough for description. The members of this genus are readily distinguished 
from the usual members of the Craniidae by their shell substance. 
Genus ACANTHOCRANIA Williams, 1943 
Acanthocrania Witi1AMs (J. Steele), U. S. Geol. Surv. Prof. Pap. 203, p. 71, 1943. 
This name was proposed to include Cranias “ornamented by fine papillae or 
fine spines.” Williams designated Crania spiculata Rowley as the type of the 
genus. 
This genus is widely distributed and is fairly abundant in the Ordovician. It 
also occurs in the higher rocks. At present the pedicle valve of the genus is not 
