NATURAL SCIENCES OP PHILADELPHIA. 25 



Archceocidaris ? In No. 12, we found spines and detached plates of apparent- 

 ly an undescribed species of this genus, but they were too much weathered to 

 show clearly the specific characters. The spines are rather slender, terete, 

 nearly straight, and provided with short scattering spinous processes, directed 

 rather obliquely outwards and forward. 

 Cottonwood Creek. 



Archceocidaris ? The spines of this species are much larger than the last, 



and apparently destitute of spinous processes. They are as much as from three 

 to four inches in length, nearly or quite straight, and not flattened or com- 

 pressed. 



Division No. 26, Manhattan and in same position on Cottonwood Creek. 



Brachiopoda. 



Discina tenuilineata n. sp. We have only seen the lower valve of this species, 

 which is extremely thin, nearly orbicular, and provided with a narrow perforation 

 extending from very near the centre about half way out to the margin. The 

 inner surface is ornamented by distant, extremely slender, distinctly elevated 

 lines of growth, arranged concentrically around a point very nearly in the mid- 

 dle of the valve. The apex of the upper valve was probably nearly central. 

 Diameter 0-50 inch. 



Locality and position. Cottonwood Creek, division No. 16. 



Discina Manhattanensisn. sp. Shell rather small, nearly circular ; upper valve 

 moderately elevated, apex rather obtusely pointed, located a little less than half 

 the diameter of the shell from the posterior edge. Surface black and shining, 

 marked by fine closely set concentric lines. Lower valve unknown. Greater 

 diameter from 0-32 in. to 0-46. 



Found in great numbers in division No. 37, opposite Manhattan, on Kansas 

 river. 



Productus splendens (.?), Norwood and Pratten, Jour. Acad. Nat. Sci. Phila. 

 N. S. vol. 3, pi. fig. 5. We refer this shell to the above species with some doubt ; 

 it is always smaller than the figure given by Norwood and Pratten, and rather 

 more convex over the visceral region of the larger valve, while the smaller valve 

 appears to want the band-like flattening around the border mentioned in the 

 description of P. splendens. The ears extend beyond the body of the shell, 

 are distinctly vaulted, and rarely have more than one spine on each, often none. 

 The spines, however, are more numerous over the surface of the larger valve, 

 being in this respect more like P. muricatus'8. and P., but both valves want the 

 concentric wrinkles represented in the figures of that species. 



This neat little Productus is found in great numbers between Fort Riley and 

 Manhattan, as well as at the latter place, in Division No. 34 ; also at various 

 horizons below that in the upper coal measures of Kansas. 



Productus Norivoodi, Swallow, Trans. Acad. Sci. St, Louis, vol. 1, p. 182. A 

 few specimens of this species in our possession have the extreme point of the 

 beak of the larger valve flattened or truncate, aa though it had in the young 

 state been attached to some marine body by that part of the shell. We have 

 also in several instances found other shells associated with this species, with 

 small discs not more than 0-20 inch in diameter, attached by the whole surface, 

 as well as by a series of small spines seen radiating from the margin. May not 

 these little bodies be the young of this species? 



We think the specimen figured by Prof. Marcou in his work on the Geology 

 of North America, plate 6, fig. 1, as P. pustidosus, is the same as the above spe- 

 cies, and quite distinct from P. pustidosus. It occurs in Kansas at various ho- 

 rizons from No. 14 far down in the upper Coal measures. We found it at Fort 

 Riley and numerous places between there and the Missouri, as well as at Leav- 

 enworth city. 



1859.] 



