DESCKIPTIOlSrS OP SPECIES. 375 



standing. Hall and Clarke" rather discredit the significance of the characters upon 

 which Marginifera is founded, and if their view is correct, a new name will have to 

 be sought for this species. 



I have tentatively added to the usual synonomy Roemer's identification with 

 P. flemingi of a shell from Texas. The figures of the Texan form are certainly 

 suggestive of Norwood and Pratten's species. 



Locality and horizon. — San Juan region (station 2196a); Hermosa formation. 

 Crested Butte district (stations 2244, 2245, 2280, 2292, 2297, 2316, 2318); Weber 

 limestone and Maroon foi'mation. Grand Eiver region (station 2824), Glenwood 

 Springs (station 2326). 



Maeginifera wabashensis Norwood and Pratten var. 



PI. V, figs. 8, 8o. 



1854. Productus wabashensis. Norwood and Pratten, Acad. Nat. Sci. Philadelphia, Jour., (2), vol. 3, 

 p. 13, pi. 1, figs. 6a-d. (Imprint of whole volume, 1855.) 

 Coal Measures: Near New Harmony, Ind. 



I have experienced great diiBculty in reaching a decision satisfactory to myself 

 in regai'd to the forms belonging to the group for which Waagen proposed the name 

 Marginifera, not onlj'^ in the matter of discriminating species, but in determining the 

 name which should be emploj^ed for them. 



In 1854 Norwood and Pratten described three species of Prodiictus belonging 

 to this group whose mutual specific relations are verj'' close. They were given the 

 names P. muricatu.^, P. .splendens, and P. wabashensis. 



Meek* places all three species in the synonymy of P. longispinus Sowerby, fol- 

 lowing Davidson's judgment in this, though, it is apparent, doing violence to his own, 

 at least in the case of P. inuricatus. Waagen <" recognizes P. wahashensis and 

 P. splendens as independent species, each of them valid and distinct from P. 

 longispinus. Freeh'' regards P. xoaba^hensis and P. splendens as identical, but as 

 certainly distinct from Sowerby's species. 



There can, •! think, be no doubt but that P. muricatus is distinct not only from 

 P. splendens and P. wahashmsis, but from P. longispinus. P. spleiidens and 

 P. wabashensis are much more closely akin to each other than is either of them to 

 P. muricatus; nor can there be much doubt that they also are distinct from P. longi- 

 spinus. Although Sowerby"' described his species as "indented in the middle," and 

 though Davidson'' included under P. longispimm shells which are both evenly convex 



a Pal. New York, vol. 8, pt. 1, 1892, p. 331. 



6 U. S. Geol. Surv., Nebraska, 1872, p. 161. 



c Geol. Surv. India, Mem. Pal. Ind., 13th series, vol. 1, 1887, p. 715. 



d Letheea Geoguostlca, 1. theil, 2. band, 2. lieferung, 1899, desc. pi. 47c, fig. 14. 



e Min. Conch., vol. 1, 1814, p. 154. 



/Pal. Soc, Mon. British Carb. Brach., pt. .5, 1857, p. 145, pi. 35, figs. 5-17. 



