SHUMARD — NEW FOSSILS. 101 



Notice of some new and imperfectly known Fossils from 

 the Primordial Zone (Potsdam Sandstone and Cal- 

 ciferous Sand Group) of Wisconsin and Missouri.* 



By B. F. Shumard, M.D. 



[May, 1862.] 

 CRUSTACEA ( T RIL BIT E S) . 



DlKELOCEniALUS LATIFRONS, n. Sp. 



Head rather large, flattened convex, having a wide border 

 in front with a gently convex rim, within which is a strong 

 groove, and between this and the front of the glabella a gent- 

 ly convex surface double the width of the marginal rim. This 

 surface is marked with fine, slightly flexuous lines, w T hich arise 

 from the groove in front and converge to the front of the gla- 

 bella. The width of the border is rather more than two thirds 

 the length of the glabella. The glabella is flattened convex, 

 truncated conical, very gently rounded at apex, sides nearly 

 straight, and the surface marked with two or three very ob- 

 scure furrows on each side of the median line. At the base 

 is an obscure transverse furrow. 



The eyes, cheeks, thorax, and pygidium, are unknown. 



Length of head, 13 lines ; length of glabella, 7^ lines ; width 

 at base, 6| lines; width at apex, 4 lines. 



This species is nearly related to D. planifrons, Billings, 

 from which it differs in having a proportionally wider front 

 margin, while the sides of the glabella converge much more 

 rapidly from base to front. Mr. Billings finds also in the Ca- 

 nadian species a curved row of punctures just within the mar- 

 ginal rim, whence arise the strice which converge to the front 

 of the glabella ; but in our specimen no traces of such punc- 

 tures are visible. 



The only specimen I have seen of this species is a cast in 

 fine grained yellowish-gray micaceous sandstone, filled with 

 remains of Conocephalites and an Orthis which resembles 0. 

 Coloradoensis, Sham. 



Geol. Pos. <jb Loc. — Primordial Sandstone (Form. No. 1 

 of Owen's Geol. Surv. of Iowa, Wisconsin and Minnesota), 

 Trernpeleau, Wisconsin. 



Arioxellds bipunctatus, n. sp. 



Small, moderately elevated; glabella convex, conical, trun- 

 cated or sometimes very gently arched at apex ; length ex- 



* Figures illustrating the species described iu this paper will appear in 

 the next number of the Transactions. 



