PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 271 
TREMATIS ELLIPTOPORA Cooper, new species 
Plate 11, H, figures 15-21 
Shell small for the genus, represented by fragmentary specimens only; sub- 
circular in outline with the surface marked by large, longitudinally elliptical pits 
increasing in size anteriorly. Pedicle valve subcircular in outline with a deep 
semicircular notch; beak concave, umbonal region gently concave, the concavity 
lessening anteriorly and laterally. Pedicle notch triangular, longer than wide, oc- 
cupied by a deeply concave plate; actual pedicle opening wide and short, some- 
what semicircular in outline. Brachial valve with swollen umbo and beak pro- 
truding slightly beyond the posterior margin; lateral profile moderately convex ; 
umbonal slopes steep; median region swollen; anterior profile broadly convex 
and with steep lateral slopes. 
Interior of pedicle valve with thickened ridge representing the strengthened 
inside of the concave plate; brachial interior with thickened posterior margin 
having a more or less deep triangular pit under the beak. Musculature not pre- 
served in either valve. All specimens too incomplete to measure. 
Types.—Holotype: 116809c; figured paratypes: 116809a,d; unfigured para- 
types: 116809b,e-h. 
Horizon and locality —Pratt Ferry formation in Alabama: 0.2 mile southeast 
of Pratt Ferry, Blocton (15’) Quadrangle. 
Discussion.—This species is characterized by the large size of the pits which 
are a feature of the ornamentation. The pits are elliptical or oval in outline with 
the long axis parallel to the shell length. The elevated space between pits is 
relatively broad. Pits on the umbo are very small. The arrangement of pits is 
crudely quincuncial. The large size and form of the pits separate the species 
from other described forms. 
A note about the pedicle valve is necessary because it is not certain that it 
belongs to this species. In color it is dark yellow like that of some of the other 
specimens which range from dark yellow to light brown. The pedicle valve is 
very thick shelled, which is another point in accord with the brachial valves to 
which it is assigned. The ornamentation, however, is not like that of the brachial 
valves. The pedicle valve shows small pits suggesting the youthful ornamenta- 
tion of the umbonal region of the brachial valves. This ornamentation is very 
lightly impressed and does not occur around the margins. Possibly the orna- 
mentation is preserved only on the more youthful parts of the pedicle valve. 
The species is represented by fragmentary material only, consisting of several 
brachial valves but only the single pedicle valve. 
TREMATIS FOERSTEI Cooper, new species 
Plate 19, D, figures 15-19 
T. huronensis Forrste (not Billings), Bull. Sci. Lab., Denison Univ., vol. 19, No. 3, p. 203, 
1920. 
Shell of about medium size for the genus, nearly circular in outline, lenticular 
in profile. Surface marked by stout radial lines, and concentric elements that de- 
