GAKBONIFEROUS SPECIES 91 



Length, 1.90 inches; breadth, 2 niches; convexity, 1.30 inches. 



This fine species may be compared with ;S'. hisiilcatus of Sowerby, some 

 varieties of which (especially those with broad depressed costfe) it more or 

 less nearly resembles. It seems, however, to be always longer in propor- 

 tion to breadth, and is much less variable in form. The most reliable dif- 

 ference observable, however, is the beautifully-granulated surface of our 

 species. I know of no nearly similar American shell with which it is neces- 

 sary to compare it. 



Loealiti/ and position. — Light-colored Carboniferous limestone, at lati- 

 tude 40° N., longitude 11.5° 20' W.; Colonel Simpson's collections. 



Spiuifer (Trigonotreta) cameratus, Morton. 



Plate 9, figs. 2, 2 a. 



Spiri/er cameratus, Morton (IS.'iG), Aiu. Jour. Sci. and Arts, XXIX, 150, pi. 3, fig. 3. — 

 Hall (1856), Pacific R. R. Report, III, 102, pi. 2, figs. 9, 12, and 13; and (1858) 

 in Iowa Geological Report, I, part ii, 700, pi. xxviii, fig. 2. — Meek (1870), iu 

 Col. Simpson's Report Expl. across the Great Basin of Utah, 353, pi. ii, figs. 

 3 a, b. 



Spirifer Meusebaclianus, Roeiner (1852), Kreid. von Texas, 88, pi. 11, figs. 7 a, h, c. 



ISpirifer triplicatus, Hall (1852), Stansbury's Report of Salt Lake Expl. Expedition, 410, 

 pi. 2, fig. 5 (by error pi. 4). 



? Spirifer fascificr, Owen (1852), Report Wiscon.sin Iowa and Minnesota, pi. 5, fig. 4 

 (Ke.vserling'i! (1840.) 



Spirifer striatus var. tripUcatus, Marcou (1858), Geol. N. Am., 49, pi. vii, fig. 3. 



Spirifer cameratus var. Kansasensis, Swallow (1807), Trans. Saint Louis Acad. Sci., II. 



f Spirifera camcrata, Derby (1874), Bull. Cornell Univ., I, No. ii, 13, pi. i, figs. 1-9, aud 14. 



The specimens that I have refeiTed to this common species are all more 

 or less broken or distorted ; but, so far as their charactei's can be made out, 

 they seem to agree so nearly with characteristic examples of Morton's species 

 from the Coal-Measures of the Mississippi Valley, that I have scarcely any 

 doubts of their identity. They all have the peculiar fasriculated character 

 of the costa;, so characteristic of S. cameratus, more or less marked, while in 

 some of them it is well defined. They seem to have the mesial fold some- 

 what less prominent, and the lateral .slopes less compressed than we usually 

 see in S. cameratus; but these are more or less variable characters in that 

 species. 



Locality and position. — Light-colored Carboniferous limestone, at Fos- 



