330 CARBONIFEROUS FORMATIONS AND FAUNAS OF COLORADO. 



AROHiEOOIDARIS TRIPLEX White? 

 1881. Arrh!>(X-irJari>! Iriph'.i: Whitp, V. S. Geog. Geol. Snrv. W. 100th Mer., Eept., vol. 3, Supp., 

 Appendix, p. xxii, pi. 4, tigs. 3«-c. 

 Carboniferous: New Mexico. 

 1895. Arch,roci(l(ir!.i lrij}le.i: Keyes, lowaAead. Sfi.,Proc., vol. 2, p. 191. 

 Upper Coal Measures: New Mexico. 



This species has been found at onlj'one locality, and the identification i,s unsatis- 

 factoiy because of the fragmentary character of the material. This consists entirely 

 of spines of unusually large proportions. The diameter is ii mm. just above the 

 ring and is still greater distally. When complete the length could hardly have been 

 less than 13 mm. , and it maj' have been greater. Comparativelj^ small spinules pro- 

 ject from the principal style at intervals of about S mm. On one important featui'e 

 I have been unable to assure myself — the character of the cross section. Of course 

 near its base the style is cylindrical. Some small weathered fragments appear to be 

 three-cornered, but in sections l^rought to view on the broken faces of the matrix 

 this feature is less distinct. Here they usually show one or two flattened sides, with 

 the rest of the outline circular. In the largest and most perfect specimen the spinules 

 appear to be arranged in rows, which are sufficiently far apart to admit of but about 

 three in the circumference. This would seem to indicate that the style was originally 

 three-sided. The .spines in the two rows in view are nearlj^ but not quite opposite. 

 Those in the same row are about 8 mm. apart, somewhat less than in the typical 

 specimen of A. triplex, and the articulating ring is transverse, instead of, as in it, 

 oblique. The nearest described species, next to A. triplex, is A. megastylus, but my 

 specimens show many more spinules than are exliibited in Kej^es's iigures, and the 

 articulating ring is much more projecting. The species also closely resembles 

 A. Gratis, but it is ^-ery much more robust, and the spinules appear to be consider- 

 ably finer. 



Locality and horizon. — San Juan region, Needle Mountains quadrangle (station 

 2188); Molas foi-mation. 



Archjeocidaris trudifer White? 



1874. Archxocidaris trudifer. White, U. S. Geog. Geol. Surv. AV. 100th Mer., Prelim. Rapt. Invert. 

 Foss., p. 17. 

 Carboniferous (Coal Measures): Camp Apache, Arizona. 



1876. Arch^oeidaris trudifer. White, Powell's Kept. Geol. Uinta Mountains, p. 89. 

 Lower Aubrey group: Confluence of Grand and Green rivers, Utah. 



1877. Archseocidaris trudifer. AVhite, U. S. Geog. Geol. Surv. W. 100th Mer., Eept., vol. 4, p. 104, pi. 6, 



figs 8a, 6. 



Carboniferous (Red Wall limestone): Camp Apache, Arizona. 

 1895. Archieocidari'! trudifer. Keyes, Iowa Acad. Sci., Proc, vol. 2, p. 191. 



Lower Carboniferous: "Camp Apache," Arizona. 

 1900. Archmocidaris trudifer. Beede, Univ. Geol. Surv. Kansas, Rept., vol. 6, p. 47, pi. 8, fig. 10. 



Upper Coal Measures (Topeka limestone): Topeka, Kans. 



