FOSSILS OF THE CLINTON GROUP. 563 



Tellinomya {Nnculaf) minima, Foerste. 



( Plate 26, Figs 8 a, b. e ; Plate 37, Figs. 13 a, b, c.| 



This form, first described in the Bulletin of Denison Univ., Vol. I, 

 is represented by only a few specimens from the Beavertown marl at 

 Huffman's Quarry. They are all casts, and the following description 

 refers to these casts: A raised line extends along the hinge margin. 

 Along this, especially in the anterior lunule, one specimen shows 

 traces of transverse teeth, but whether the series is interrupted at the 

 beak or not is unknown. In the po-terior lunule two lateral ridges 

 branch off from the median one. The posterior lunule has a lanceolate 

 outline, the anterior one is very broadly ovate. The shell is oblong, 

 much longer than high. The convexit}' is most marked at the beak. 

 The length of the largest specimen is 3.9 mm., the height is 2.7 mm., 

 rnd the thickness from valve to valve 1.9 mm. The beak is near the 

 anterior fourth of the cast. 



Tetlinomya (Ntcacla?) socia/is, sp. nov. 



(PL.te 37, Figs. 12 a, b, c.) 



The great majority of the minute lamellibranchs found in the 

 Beavertown marl at Huffman's Quarry, and in the corresponding layer at 

 Geo Young's Quarry, on the Carrollton Pike west of Soldiers' Home, 

 belong to a species quite distinct from the last. All are casts. A raised 

 line extends along the hinge margin, and shows transverse teeth plainly 

 both in the anterior and in the posterior lunules, but whether the series 

 was interrupted at the beak or not could not be determined. The pos- 

 terior lunule has a lanceolate outline though narrower than in T. minima. 

 The anterior lunule is of almost linear outline, and this alone will readily 

 distinguish the two marl species. The form of the shell is also different — 

 being triangular oval. The convexity is most marked at the beak. The 

 largest shell is 3.5 mm. long, the height is about the same, the thickness 

 is 1.9 mm. from valve to valve. The muscular impressions are well 

 shown, that of the anterior muscle being narrower. 



Tellinomya {Nuciua?) Clinton' nsis, sp. nov. 



i Plate 37, Fig. 10.) 



In the collections made by Prof. K. W. Claypole in the ferruginous 

 Clinton limestone near MifHintown, Juniata Co., Penna., occurs a valve of 

 a decidedly nuculoid shell. Its precise generic relations could not be deter- 

 mined owing to the fact that the row of teeth is well shown only along the 

 posterior hinge line, and its interruption or continuation at the beak could 

 'not be determined. In Middle Silurian rocks Tellinomya is however apt to 

 be a more common genus than Nucula, and hence the reference to that 



