6o6 TRANS. ST. LOUIS ACAD. SCIENCE. 



limestones occurring along the Rosseau creek, near Mt. Albion, 

 six miles east of Hamilton. 



Note. — In mode of branching and arrangement of cross-bars this spe- 

 cies more nearly resembles those of Dictyofiema than any Brvozoon that 

 I have seen. But the absence of corneous matter, of solid axis, and the 

 graptolitic cellules, are at once noticeable. 



LiNGULA INGENS, nOV. Sp. 

 Plate 8. Fig. 6. 



Shell subelliptical and large, with sides nearly parallel, and 

 converging with a gentle convex slope to the beak, at an angle a 

 little less than ninety degrees, with apex rounded, the sides con- 

 verging below in a circular form. Width of shell two-thirds the 

 length. Surface smooth, glistening, and marked with numerous 

 very fine, slightly diverging longitudinal stride. 



A narrow, shallow, concave sinus extends from the apex to 

 near the base of one valve. The surface is also marked with in- 

 frequent concentric interruptions of growth which become more 

 numerous and take the form of striaj near the margins, and bend 

 back towards the beak. The length is 35 and the width 23 mil- 

 limetres. 



Formation and Locality. — This fossil was obtained by Col. Grant 

 from the "chert-bed" of the Niagara formation at Hamilton, Ont. 



DiSCINA CLARA, nOV. Sp. 

 Pl.ite 8, Figs. .5 & 5a. 



Shell circular, both valves more or less conical with apex cen- 

 tral or nearly so. The peduncular groove (on lower valve) strong, 

 with nearly parallel sides, extending from the centre to half the 

 distance to the margin ; upper valve with surface unbroken. Both 

 valves are marked by fine concentric striic which increase in 

 strength as they approach the margin (the central portion appear- 

 ing smooth except imder a lens). The grooves are much wider 

 than the ridges. The interior of shell is nearly smooth, being only 

 slightly marked by faint lines corresponding to' the ridges on the 

 exterior side. The upper valves are usually a littler smaller than the 

 lower, the largest ventral valves being two centimetres in di ame- 

 ter, and the peduncular sinus from three to four millimetres long, 



This species resembles the British D. forbcsii., but that species 

 has the apex of lower valve eccentric. It has a closer resem- 

 blance to the Trenton species D. circe, but the peduncular groove 



