GIRTY, NEW CARBONIFEROUS FOSSILS 235 



Kirkbya reflexa sp. nov. 



Shell rather large, strongly transverse. Dorsal border straight, very nearly 

 as long as the greatest width. Ventral margin gently convex across the middle, 

 more strongly curved toward the ends. Ends very nearly symmetrically 

 formed. Cardinal angles almost equal, the anterior being slightly more acute 

 than the other. A deep groove surrounds the ventral and lateral borders, the 

 marginal portion of the shell being bent upwards in a broad border or 

 flange. The remainder rises gradually and regularly to the middle of the 

 dorsal border, and this portion of the shell would have the shape of one half 

 of a spreading cone, if it were not that the posterior (?) half of the cone is 

 somewhat compressed, which makes the most elevated portion into a curved 

 oblique ridge. 



The surface is finely and deeply reticulated, the apertures increasing in 

 size toward the reflexed border, upon which they are prolonged into relatively 

 large, transverse grooves, so that the border looks fluted or perforated, 

 though having the margin entire. 



Kirkbya simplex sp. nov. 



Shell small, transverse. Dorsal border long and straight, converging an- 

 teriorly (?) with the gently convex ventral outline. Ends nearly equally 

 rounded, the anterior being narrower and more strongly curved. Convexity 

 moderate, chiefly marginal, regular, without sulci or tubercles. Surface 

 strongly and finely reticulate, except marginally, where the shell seems to be 

 smooth and dense. Position of median pit not determined. 



Amphissites gen. nov. 



A number of ostraeod shells in the fauna -of the basal Fayetteville 

 shale belong to types which have been loosely referred to the genus 

 Kirl-hya, but they really appear to represent three generic or snbgeneric 

 groups. Kirl-hya itself is described as having the right valve larger than 

 the left and overlapping it. This is the condition of K. Hndahli var. 

 arl-ansana. The shell described below as Amphissites rugosus has the 

 two valves equal, meeting each other along a line, neither one overlap- 

 ping the other. It is furthermore distinguished by having the surface 

 marked by a number of tubercles in addition to the fine reticulations. 

 On l)oth these accounts, it seems that this form can readily and advan- 

 tageously be distinguished from Kirl-hya proper. The third type is repre- 

 sented by Glyptopleura inopinata. which has the left valve overlapping 

 the right. Conjoined with this difference in configuration is one of 

 sculpture, the sides being without knobs or plications, l)ut ornamented 

 with oblique, inosculating costa^ instead of the fine reticulations and 

 flanges of the other types. 



Type. — Amphissites rugosus. 



