DESCRIPTIONS OF SPECIES. 293 



to be comparatively rare, and the fossils which have thus far come into my hands 

 are few in number and not in good condition. One important distinction resides in 

 the fact that Sp. peculiaris is marked as to its surface \)j regular, closely arranged, 

 concentric lamellae, while the Westei'n specimens appear to be quite smooth. Thej^ 

 probably constitute an undescribed species, but it seems wiser to await more abundant 

 material before making detailed comparisons or assigning a new name. So far as 

 the available specimens, which are very variable, are characteristic, this form can 

 scarcely belong to Sp. suiorbicularis or to Sj). subcardiformis, and in general con- 

 figuration, at least, it most closely resembles Sp. peculiaris. 



In the above remarks, wherever the Colorado material is involved, T have had in 

 mind especially that from the Crested Butte region. From the San Juan region but 

 two very imperfect examples have so far come to hand. One of these is so poor as 

 to render its relation to Sp. 'peculiarly no more than a probability, while the other, 

 though probably of the svhorbicularis type, shows a distinct median rib in the ventral 

 sinus, a character which 1 have yet observed neither in typical Sp. peouUaris nor in 

 the material provisionally allowed to remain under the same name. 



Locality and horizon. — San Juan region (stations 2382, 2384?); Ouray limestone. 

 Crested Butte district (station 2358) ; Leadville limestone. 



SYRINGOTHYEIS Winchell, 1863. 



Stringothyeis carteri Hall. 



1857. Spirifer carteri. Hall, New York State Cab. Nat. Hist., 10th Kept., p. 170. 



Waverly sandstone: Licking County, Ohio. 

 1860. Spirifer (Cijrtiu?) hamiibulensis. Swallow, Acad. Sci. St. Louis, Trans., vol. 1, p. 647. 



Lithographic limestone: Marion County, Mo. 

 1863. Syringothyris iypa. Winchell, Acad. Nat. Sci. Philadelphia, Proc, p. 7. 



Base of Burlington limestone: Burlington, Iowa. 

 1865. Syringolhyriis cuspidaiua. Meek, Acad. Nat. Sci. Philadelphia, Proc, p. 275. 

 1867. Syringolhyr'is cimpidatas. Meek, Am. Jour. Sci., (2), vol. 43, p. 407. 

 1870. Spirifera carteri. Winchell, Am. Phil. Soc, Proc, vol. 11, p. 2.52. 



Waverly group: Sciotoville and Rockville, Ohio; near Shafers, Pa. 

 1870. Syringothyris typa. Winchell, Am. Phil. Soc, Proc, vol. 11, p. 252. 



Waverly group: Newark and Sciotoville, Ohio; near Shafers, Pa. 

 1875. Spirifer carteri. Meek (partim), Pal. Ohio, vol. 2, p. 285 (not his figures — S. texta Hall). 



Waverly group: Ohio. 

 1877. Spirifer euspidatusf Meek, U. S. Geol. Expl. 40th Par., Rept., vol. 4, p. 87, pi. 3, figs. 11, 11a. 



Carboniferous or Devonian limestone: White Pine Mountains, Treasure Hill, Nevada. 

 1884. Syringothyris euspidata. Walcott (not Martin), U. S. Geol. Surv., Mon., vol. 8, p. 219, pi. 3, 

 fig. 11. 



Lower Carboniferous: Eureka district, Nevada; near Clendenin, Mont. 

 1888. Syringothyrii cuspidiitus. Herrick (partim), Sci. Lab. Denison Univ., Bull., vol. 3, p. 41, pi. 1, 

 fig. 7; pi. 2, fig. 17 (not pi. 5, figs. 4-7 — S. herricki). 



Waverly group: Licking County, Ohio. 



