19 



in the presence of dimorphous pores upou the axial portion of the porif- 

 erous side of tlie stems and branches, and in the absence of the three 

 lon,ijitudinal, raised lines, which distinguish that species. 



Position and localiti/. — Carboniferous strata at the continence of White 

 Mountain and Black Elvers, Arizona. 



Genus Polypora McCoy. 



POLYPOEA STRAGULA {sp. Hov.) — Poljzoary apparently flabelliform; 

 longitudinal branches bifurcating witii more or less irregnlarity in dif- 

 ferent parts of the polyzoary; dissepiments little, if any, more than half 

 as wide as the branches ; fenestrnles oval or oblong, the proportions of 

 length and width varying in different parts, from about one-quarter 

 longer than wide to twice as long as wide. Poriferous side of branches 

 furnished witli from four to six rows of small, thick-set pores of uniform 

 size, arranged more nearly in rows obliquely than vertically. Dissepi- 

 ments bearing a conple of pores near their junction with the branches, 

 and rarely one or two others along their middle portion, which is often 

 slightly ridged. 



Fenestrnles varying in size in different parts of the polyzoary, but 

 average about six longitudinally in the space of a centimeter. 



This species occurs in tlie Upper Coal-Measures of Iowa, Missouri, and 

 Nebraska, and is the one referred to by Dr. Geinitz, (Carbonfonnat. und 

 Dyas in Neb.) to Poh/pora biarmica Keyserling. 



Position and locdliti/. — Carboniferous strata, contiuence of "White 

 Mountain and Black IJivers, Arizona. 



BEACHIOPODA. 



Genus Chonetes Fischer. 



Chonetes platvnota {sp. n')i\) — Shell rather under average size, 

 transversely suboval or indistin(;tly four-sided ; hinge-line usually about 

 equal to the greatest width of the shell, often slightly exceeding it, and 

 occasionally shorter. 



Ventral valve moderately convex, flattened a little toward the hinge- 

 extremities, without a ])roper mesial sinus, but, in place of it, there is a 

 mesial flattening or slight bending iq»ward, at the front only, which 

 straightens the front border a little ; beak not [)rominent ; area of 

 moderate width wider than that of the dorsal valve, bearing on its pos- 

 terior margin five or six rather small oblique tube-spines upon each 

 side of the beak. 



Dorsal valve almost flat, oftener a little convex than concave, especi- 

 ally from side to side ; mesial fold represented only in adult shells, and 

 in them merely by a very sliglit elevation of the front, causing its mar- 

 gin to follow that of the ventral valve in a gentle sinuosity; surface of 

 both valves marked by numerous fine, obscure, radiating striae and 

 occasional imbricating lii\es of growth. 



This species is readily distinguished from others by its flat or slightly 

 convex dorsal valve. 



Length, nine millimeters ; width, twelve millimeters. 



Position and locality. — Strata of the Carboniferous period, near Santa 

 Fe and near Salt Lake, New Mexico. 



Genus Rhynchonella Fischer. 



Rhynchonella Wasatchensis {s}). noi'.)— Shell under medium size, 

 sublenticular or subglobose ; valves nearly equally convex; length 



