HUDSON RIVER BEDS NEAR ALBANY 577 



T u r r i 1 e p a s (?) f i 1 o s u s , sp. n. {see pi. 2, fig. 13, 14, 15). 



In the lower Utica shale of Mechanicsyille, two plates were 

 found, which in size, outline and surface ornamentation greatly 

 differ from the minute plates of Lepidocoleus jamesi^ 

 associated with them in great number. Both plates, though of 

 different size, are so clearly alike in outline and sculpture that 

 they undoubtedly belong to the same species. 



Plates obliquely subtriangular, comparable in outline to an 

 isosceles triangle with the apex pushed to one side; the nucleus 

 falling into the apex^ and the two legs standing nearly vertical 

 on the slightly convex base; the lengthened side strongly convex,, 

 the shortened nearly straight; surface marked by strongly ele- 

 vated, very regular concentric lines, which have multiplied more 

 rapidly on the posterior side. 



Dimensions. The smaller specimen measures 4 mm along the 

 base, and 4.5 mm along the vertical side; the larger 7 mm and 9 

 mm in the same directions. 



Both valves figured differ markedly from the typical plates of 

 Turrilepas by their outline, the absence of the sigmoidal 

 curvature in the base, their relatively larger size, and the char- 

 acter of the concentric striae, which appear not as the edges of im- 

 bricating layers, but as strongly elevated lines with deep^ even in- 

 terspaces and by the conical shape which they proibably possessed 

 originally; for they present the) appearance of convex bodies 

 which became flattened in fossilization. This is specially dis- 

 tinct in the smaller specimen (pi. 2, fig. 13), where a median 

 furrow or break separates two differently convex halves. In all 

 these features they agree with another group of valves which 

 have been doubtfully referred to Turrilepas by Whitfield 

 {Armals New York acad. sci. 1882. v. 2. no. 8. p. 217) and by 

 Hall and Clarke {Pwl N. Y. 1888. 7:219). The latter authors 

 remark " that it is difficult to see how the combination of 

 these subconical bodies in vertical ranges could produce such 

 a scaly peduncle or capitulum as existed in Turrilepas" 

 and point out their resemblance with Spathiocaris. This 

 form (Turrilepas (?) newberryi), from which ours dif- 



