1896.] -^5d [Smith. 



The best preserved specimens are small, being only the inner whorls 

 of large individuals, since the body chamber is not seen on any of them. 

 Dimensions of a small specimen, ligured on PI. xxi, Fig. 2 : 



Dimensions. mm. 



Diameter 28 



Height of the last whorl from umbilicus 19 



Height of the last coil from the top of the inner whorl. . 11 



Position and Localiti/. — Several specimens of this species were found 

 in the Lower Coal Measures of Conway county, Ark., 5 N., 16 W., sec- 

 tion 17, centre of the north half. 



Oenus Ephippioceras, Hyatt. Ephippiocerasf erratum Cox. Nautilus 

 ferratus Cox, Oeol. Surr. Kentucky, iii, Fig. 574, PI. x, Fig. 2. 

 Ephippiocerasf erratum Cox, A. Hyatt, Proc. Boston Soe. JVat. Hist., 

 1883, p. 290. 



A single large specimen that probably belongs to this species was 

 found in the Lower Coal Measures of Conway county. Ark., 5 N., 

 16 W., section 17, centre of the north half. Owen, in his Report on a 

 Geol. Reeon. Arkansas, Vol. i, p. 68, cites NaMtilus ferratus from a bold 

 point three (?) miles nortliAvest of Searcy, "White county. The rocks of 

 that region are now known to belong to the Lower Coal Measures. 



Nautilus sp. 



In the Upper Coal Measures of Crawford county, Ark., 10 N., 30 W., 

 section 10, southeast quarter of northeast quarter, were found frag- 

 ments of a Nautilus too imperfect even for reference to any of the 

 genera into which the old genus Nautilus has been split up. 



Genus Ortiioceuas, Breynius. Ortliocevas crihrosum Geinitz, Carbon. 

 «.. Dyas in Nebraska, p. 4. Orthoceras cr-ibrosum Geinitz, Meek, V. 

 8. Oeol. Surv. Nebraska, p. 234, PI. xi. Fig. 18. 



In the Upper Coal Measures of Poteau mountain, Indian Territory, 

 were found specimens of Orthoceras, showing the peculiar indentations 

 of surface supposed to be characteristic of this species. The markings 

 seem to be due to the growth of a bryozoon on the shell, for when 

 magnified they show six-sided cells. Meek, op. cif., p. 234, stated his 

 belief that this marking is accidental. 



OHhoceras conf. rushense McChesney, New, Pal. Foss., p. 08. Orthoceras 

 rushense, C. A. White, Bull. 77, U. S. Geol. Survey, p. 22, PL ii, 

 Figs. 14-16. 



This species was described originally from the Coal Measures of 

 Indiana and Illinois, and Dr. C. A. White found it in the Permian of 



