Dcficriptlons of Species. 33 



Cylindrites (?) sp. indet. 



The writer has collected from the hase of tlie Glen Rose heds 

 ill Parker county a few specimens of a small gasteropod very 

 miicli resemhliii,!^ Ci/lindrUes bvU.atux T^yc. and Mort. Unfoi'tu- 

 nately tlie specimens have been lost. 



Buccinopsis (?) parryi Coniud. 

 Plate VI, Fio-. 1. 



U. S. and INIexican Boundary Report, ]). 15S, plate xiii, fi.us. 

 4a, b. 



B. Conrndl Hill. Arkansas Geolo(2;ical Survey, Annual Report 

 1888, vol. ir, p. 130, jdate iii, figs. 2, 2a. 



Conrad describes this species as follows : 



" Sul)pyriform ; longitudinally undulated and ornamented 

 with rugose, revolving lines, spire scalaril"orni ; apcrtui'e large 

 and i^atulous.'' Conrad also says: "Under this name I have 

 described a cast wliich cannot l)e referred to an}^ known genus ; 

 it is certainly not a true Buccinopsis, nor can its generic cliar- 

 acter be determined because of poor ])reservation." 



The writer has found casts of this form -in great aJjundanccin 

 the lower fossiliferous horizons of the Glen Rose 1/ed at gy|)sum 

 bluffs of the Little Missouri, in Ai'kansas, and at Glen Rose. In 

 some instances the casts show marks in the shape of depressions 

 extending across the lower whorl and the suturc'S are very deep 

 and distinct. The whorls and spire of a more perfect specimen, 

 sliown in plate vi, fig. 1, are six in number and very flat 

 and angular at their upper edge. Whatc'ver may Ite the true 

 generic i)osition of tliis form, it is a very useful stratigraphic aid 

 to the student of the Glen Rose beds. The form is readily dis- 

 tinguishable from Tijlodoma pedernaUs Roemer by its greater 

 •,iuml)er of whorls and entirely different outline of tlie a[)erture. 



Tylostoma pedernalis (Roeiner). 



Plate VI, Fig. 2. 



Natlca pedcrnalk and N. pi;T[/ra)idls Roemer. Kreidebildungen 

 von Texas, p. 43, plate iv, figs, la, b ; plate iv, figs, la., b. 



" Sliell large, ovate; whorls flat, angular above; lowest or 

 basal whorl three times as high as the spire; sjtire composed of 

 three coils. Aperture, elongate ovate." — Roemer 



5— Biol. Soc. Wash., Vol. VIII, 189;i. 



