DESCRIPTIONS OP SPECIES. 395 



1872. Spirifer (Martinia) planoconvexus. Meek, U. S. Geol. Surv. Nebraska, p. 184, pi. 4, figs. 4a, b, 

 pi. 8, figs. 2a, b. 

 Upper Coal Measures: Nebraska City, Bennett's Mill, Wyo. ; Cedar Bluff, Rock Bluff, Platts- 



mouth, Brownville, Otoe City, Rulo, Bellevue, and Omaha, Nebr. 

 Coal Measures: Iowa; Missouri; Kansas; Pittsburg, Pa.; West Virginia. 



1874. Spirifera {Martinia) planoconvexa. Derby, Cornell Univ., (Science) Bull., vol. 1, No. 2, p. 19, 



pi. 8, figs. 12, 16, 18; pi. 9, fig. 7. 

 Coal Measures: Bomjardim and Itaitiiba, Brazil, and Pichis River, Peru. 



1875. Spirifer {Martinia) planoconvexus. White, U. S. Geog. Geol. Surv. W. 100th Mer., Rept., vol. 4, 



p. 135, pi. 10, figs. 3a-c. (Whole volume published in 1877.) 

 Carboniferous: Near Santa F6, N. Mes.; Elko Mountain, Nevada. 

 1884. Spirifer {Martinia) planoconvexa. White, Geol. Surv. Indiana, 13th Rept., p. 134, pi. 32, figs. 

 23-24. 

 Coal Measures: Indiana. Occurs from Virginia to Utah and New Mexico. 

 1887. Spirifera {Martinia) planoconvexa. Herrick, Sci. Lab. Denison Univ., Bull., vol. 2, p. 46, pi. 1, 

 fig. 12. 

 Coal Measures: Flint Ridge, Ohio. 



1893. Amhocoelia planoconvexa. Hall and Clarke, Pal. New York, vol. 8, pt. 2, p. 58, pi. 39, figs. 10-15. 



(Advance distribution in fascicles.) 

 Coal Measures: Springfield, 111.; Manhattan, Kans. 



1894. Ambocoelia. planoconvexa. Hall and Clarke, Int. Study of Brach., pt. 2, pi. 31, figs. 14-17. 

 Coal Measures: Illinois; Kansas. 



1895. Spirifera planoconiexus. Keyes, Missouri Geol. Surv., vol. 5, p. 85. (Date of imprint, 1894). 

 Upper Coal Measures; Kansas City, Mo. 



1895. Amboccelia planoconvexa.. Hall and Clarke, Pal. New York, vol. 8, pt. 2, p. 56, pi. 39, figs. 10-15. 



Coal Measures: Springfield, 111.; Manhattan, Kans. 

 1900. Ambocoelia planoconvexa. Beede, Univ. Geol. Surv. Kansas, Rept., vol. 6, p. 101. 



Upper and Lower Coal Measures: Fort Scott, Fredonia, Eudora, Lawrence, Leoompton, Topeka, 

 Emporia, Kans. 



Small shells more or less closely resembling this species were collected at several 

 localities. The nature of the surface ornamentation or other chai'acters has con- 

 vinced me that they are merely j'oung individuals of Reticularia, with large forms of 

 which thej^ are in most cases associated. Occasionally the evidence was less conclu- 

 sive than others, but using such characters as the fossils still retained, I have identi- 

 fied A. j>laniconvexa at but two localities, where, however, its presence is tolerably 

 certain. It is nevertheless possible that this species has really a somewhat better 

 representation than 1 was led to believe. It is abundant at station 2282 in the San 

 Juan region (Rico quadrangle. Sandstone Mountain section).. 



Locality and liorizon.- — San Juan region (stations 2220, 2282); middle portion of 

 the Hermosa formation. 



