19 



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

 erous side of the sterns and branches, and in the absence of the three 

 longitudinal, raised lines, which distinguish that species. 



Position and locality. Carboniferous strata at the confluence of White 

 Mountain and Black Elvers, Arizona. 



Genus POLYPORA McCoy. 



POLYPORA STRAGULA (sp. nov.} Poljzoary apparently flabelliform; 

 longitudinal branches biftircating with more or less irregularity in dif- 

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

 as wide as the branches ; fenestrules 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 with 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 couple of pores near their junction with the branches, 

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

 slightly ridged. 



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

 average about six longitudinally in the space of a centimeter. 



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

 Nebraska, and is the one referred to by Dr. Geiuitz, (Carbonformat. und 

 Dyas in Net).) to Polypora biarmica Keyserling. 



Position anfi locality. Carboniferous strata, confluence of White 

 Mountain and Black Eivers, Arizona. 



BEACHIOPODA. 



Genus CHONETES Fischer. 



CHONETES PLATYNOTA (sp. nov.) Shell rather under average size, 

 transversely suboval or indistinctly 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 proper mesial sinus, but, in place of it, there is a 

 mesial flattening or slight bending-upward, at the front only, which 

 straightens the front border a little ; beak not prominent ; 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, ofteuer 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 slight 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 strisB and 

 occasional imbricating lines 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 EHYNCHONELLA Fischer. 



EHYNCHONELLA WASATCHENSIS (sp. nov.) Shell under medium size, 

 sublenticular or snbglobose ; valves nearly equally convex ; length 



