92 IOWA GEOLOGICAL SURVEY 



Bothriolepis nitida (Leidy). 



1856. Stenacanthus nitidus J. Leidy, Proc. Acad. Nat. Sci. Philad. 8, p. 11, 



and Journal, ser. 2, 3, p. 164, pi. 16, figs. 7, 8. 

 1856. Holoptyehius americanus (pars) J. Leidy, Ibid., p. 163, pi. 17, fig: 4. 

 1889. Bothriolepis leidyi J. S. Newberry, Monogr. U. S. Geol. Surv. 16, p. Ill, 



pi. 18, fig. 2; pi. 20, figs. 1-5. 

 1891. Holonema rugosa E. D. Cope (errore), Proc. U. S. Nat. Mus., 14, p. 456, 



pi. 30, fig. 7. 

 1893. Bothriolepis canadensis H. S. Williams [errore), Amer. Jour. Sci. ser. 3, 



46, p. 286, text-fig. 5. 

 1899. Bothriolepis leidyi C. R. Eastman, 17th Ann. Rept. N. Y. State Geol. 



p. 324. 

 1907. Bothriolepis nitida C. R. Eastman, Mem. N. Y. State Mus. 10, p. 50, pi. 



3, fig. 4; pi. 7, figs. 1, 3. 



Ail imperfectly definable species, known only by fragments of 

 the dermal armor and appendages. Superficial ornament con- 

 sisting of fine stellate tubercles fused into nodose vermiculating 

 ridges. Pineal plate relatively large and semi-circular in out- 

 line. Form and general proportions of pectoral appendages as 

 in the preceding species, except that only the external margin 

 is serrated. 



This species appears to have equalled, or even exceeded the 

 average of B. canadensis in size, and displays a similar orna- 

 mentation. The stellate character of the tubercles rarely ap- 

 pears in worn specimens, and the ornament is coarser in large- 

 sized than in smaller or immature individuals. Only a few 

 fragmentary examples of the headshield have been obtained, 

 and nearly all of the detached body plates show evidence of 

 post-mortem rolling and sorting by current action. As already 

 noted by Newberry and Smith Woodward, the large antero- 

 dorsomedian plate is numerically more abundant than any of the 

 others. Its more frequent preservation is perhaps to be ac- 

 counted for by the solidity imparted to it by the presence of a 

 strong median carina along its visceral side. The plate imme- 

 diately following behind is keelless, and as a corollary fact, 

 is far less commonly preserved. 



Formation and locality. Catskill of Tioga county, Pennsyl- 

 vania, and same formation in Delaware county, New York. 



