DESCRIPTIONS OF SPECIES. 349 



1884. Derhyia crassa. Waagen, Palseontologia Indica, ser. 13, vol. 1, p. 592. 



1887. Semipronites crassus. Herrick, Sci. Lab. Denison Univ., Bull., vol. 2, p. 50, pi. 2, fig. 19. 

 Coal Measures: Flint Eidge, Ohio. 



1888. Streptorhynchus crenistria. Keyes, Acad. ISTat. Sci. Philadelphia, Proc, p. 229. 

 Lower Coal Measures: Des Moines, Iowa. 



1891. Streptorkynchus erassum. Whitfield, New York Acad. Sci., Ann., vol. 5, p. 580, pi. 13, figs. 



11, 12. 

 Maxville limestone: Ohio. 



1892. Derbya crassa. Hall and Clarke, Int. Study of Braoh., pt. 1, pi. 17, figs. 1-4, 9. 

 Upper Coal Measures: Kansas City, Mo. ; Winterset, Iowa. 



1892. Derbya crassa. Hall and Clarke, Pal. New York, vol. 8, pt. 1, pi. 10,flgs. 10, 11; pi. IIA, figs. 



28-33; pi. IIB, figs. 23, 24; pi. 20, figs. 12, 13. 

 Upper Coal Measures: Near Kansas City, Mo., and Winterset, Iowa. 



1893. Streptorhynchus erassum. Whitfield, Geol. Surv. Ohio, Kept., vol. 7, p. 468, pi. 9, figs. 11, 12. 

 Maxville limestone: Ohio. 



1895. Streptorhynchus crenistria. Keyes, Missouri Geol. Surv., vol. 5, p. 67, pi. 38, figa. 8a-h. (Date 



of imprint 1894. ) 

 Coal Measures: Kansas City, Clinton, and Lexington, Mo. 



1896. Derbya crassa. Smith, Leland Stanford Junior Univ. Pub.; Cont. Biol. Hopkins Seaside Lab., 



No. 9, p. 28. 



Upper Coal Measures :»Poteau Mountain, Indian Territory. 



Lower Coal Measures: Conway County, Ark. 

 1896. Derbya crassa. Smith, Am. Phil. Soc, Proc, vol. 35, p. 238. 



Upper Coal Measures: Poteau Mountain, Indian Territory. 



Lower Coal Measures: Conway County, Ark. 

 1900. Derbya cra.ssa. Beede, Univ. Geol. Surv. Kansas, Kept., vol. 6, p. 62, pi. 8, figs. 11, lib. 



Upper and Lower Coal Measures: Fort Scott, Kansas City, Lawrence, Topeka, Kans. 



This species appears in our collections at many localities, but it is usually rather 

 rare. Though abundant in the Crested Butte region (stations 2307 and 2320), at 

 Glen wood Springs (2193a), and at Ouray (2195a), it is somewhat crushed and poorly 

 preserved. Specifically it agrees with the Mississippi Valley variety in every 

 essential. 



The material from Leadville is both scanty and poor, and the identification in 

 one or two cases may not be correct. 



Locality and horizon. — San Juan region (stations 2197, 2203, 2219, 2220, 2233, 

 2246, 2247, 2284, 2332); throughout the Hermosa formation. Crested Butte district 

 (statio.ns 2280, 2293, 2303, 2307, 2320); Weber limestone and Maroon formation. 

 Leadville district (stations 2250, 2252, 2265, 2275); upper and lower portions of the 

 Weber formation. Ouray (station 2195a) ; Hermosa formation. Grand Eiver region, 

 Glenwood Springs (station 2193a). 



