DESCRIPTIONS OF SPECIES. 473 



defined in F. helium, being, in fact only slightly different from the revolving striae 

 with which thej" regular!}' decussate, forming indistinct nodes at the points of inter- 

 section. The revolving stri^ in P. helium are somewhat stronger and coarser, while 

 the transverse markings go nearly straight across instead of being curved, with a 

 backward inclination. The slit band also is marked by strong rugte alternating with 

 those of the lateral surface, while the slit band of P. ourayenm, though marked b}^ 

 striae, is but slighth' rugose. 



Locality and hx/nzon. — Near Ouray at about the same localitj^ and horizon as 

 station 219.5. • 



Patellostium montfoetianum Norwood and Pratten. 



1855. Bellerophon montforliamis. Norwood and Pratten, Acad. Nat. Sci. Philadelphia, .Tour., (2), vol. 3, 

 p. 74, pi. 9, figs. 5a-c. 



Coal Measures: Galatia, 111., and 5 miles below New Harmony, Ind. 

 1866. Bellerophon montfortianus. Geinitz, Carb. und Dyas in Nebraska, p. 8, tab. 1, fig. l.S. 



Coal Measures: Nebraska City, Nebr. 

 1866. Belleroplion iiita-lineatm. Geinitz, Carb. mid D3'as iu Nebraska, p. 8, tab. 1, fig. 14. 



Coal Measures: Nebraska City, Nebr. 

 1872. Bellerophon monlfortiamis. Meek, U. S. Geol. Surv. Nebraska, p. 225, pi. 11, figs. 15 (12?). 



Upper Coal Measures: Nebraska City, Nebr. > 



Coal Measures: Nebraska, Kansas, Iowa, Missouri, and Illinois. 



Lower Coal Measures: West Virginia. 

 1876. Bellerophon nionlforlianus. White, Powell's Kept. Geol. Uinta Mountains, p. 92. 



Upper Aubrey Group: Confluence of Grand and Green rivers, Utah. 



1887. Bellerophon montfortianus. Herrick, Sci. Lab. Denison Univ., Bull., vol. 2, p. 19, pi. 2, fig. I; pi. 5, 



fig. 8. 

 Coal Measures: Flint Ridge, Ohio. 



1888. Bellerophon montforlimnin. Keyes, Acad. Nat. Sci. Philadelphia, Proc, p. 235. 

 Lower Coal Measures: Des Moines, Iowa. 



1891. Bellerophon montfortianus. White, U. S. Geol. Surv., Bull., No. 77, p. 26, pi. 3, figs. 15, 16. 



Permian: Goodwin Creek, Baylor County, Tex. 

 1891. Bellerophon montfortianus. Keyes, Acad. Nat. Sci. Philadelphia, Proc, p. 254. 



Lower Coal Measures: Des Moines, Iowa. 

 1895. Bellerophomnontfortianus. Keyes, Missouri Geol. Surv., vol. 5, p. 151. ( Date of imprint, 1894. ) 



Upper Coal Measures: Kansas City, Mo. 

 1897. Palellostium montfortanus. LTlrich, Geol. Nat. Hist. Surv. Minnesota, Final Kept., vol. 3, pt. 2, 

 p. 854. 



Coal Measures. 

 1899. Palellostium monifortianum. Girty, U. S. Geol. Surv., Nineteenth Ann. Kept., pt. 3, p. 589. 



Though the material representing this species is imperfect, the identification may 

 be considered fairly reliable in some cases. A poorly preserved individual found at 

 station 2275 in the Tenmile district has been referred to P. montfortianum with 

 doubt. It ma\' be a verj^ large example of P. helium. 



