Smith.] ^"^ [Oct. 2, 



The beak is sharp, and projects beyond the cardinal margin ; the ribs 

 number about twelve, and are rather coarser than those shown iu Miller 

 and Faber's figures. 



Aviculopeeten occidentalis Shumard, Geol Survey Missovri, 1855, Part 

 ii, p. 307, PI. C, Fig. 18. 



This species is very common in the Coal Measures from Pennsylvania 

 to Arizona ; in Arkansas it was found in the Lower Coal Measures of 

 Conway county, 5 N., 16 W., section 17, northwest quarter ; about four 

 miles southeast of Morrillton, and 6 N., 16 W., section 29, east bank of 

 Arkansas river, about one mile below the Old Lewisburg ferry, in the 

 Lower Coal Measures. 



Genus Lima. Lima renf era ^hwiiVavH. Lima retif era '^\i\\i\\ay(\, Trans. 

 St. Louis Ac. Sc, i, p, 314. Crenipecten retiferus Shumard, sp., S. 

 A. Miller, If. Amer. Geol. and Pal., 1889, p. 473. 



Lima retifera is characteristic of the Coal Measures in Kansas, Illi- 

 nois, Nebraska, Texas, etc., and was also found iu the Upper Coal 

 Measures of Poteau mountain, Indian Territory. 



Genus Macrodon, Lycett. Macrodon carhonarius Cox, sp. Area car- 

 bonaria Cox, Geol. Sure. Kentucky, iii, p. 567, PL viii, Fig. 5. Ma- 

 crodon carhonarius Cox sp., F. B. Meek, Pal. Ohio, ii, p. 384. 



This species resembles so closely M. obsoletns Meek, Pal. 0/iio, ii, 

 p. 334, PI. xix, Fig. 9, as to raise doubts as to their being different 

 species. They are both found in the Coal Measures, in the upper part 

 of which several specimens of M. carhonarius were found on Poteau 

 mountain, Indian Territory. This species was also found in the Lower 

 Goal Measures of Conway county. Ark., 5 N., 16. W., section 17, north- 

 west quarter. 



Macrodon obsoletus Meek, Pr/?. Oliio, ii, p. 334, PI. xix. Fig. 3. 



This species, which is found in the Coal Measures of West Virginia 

 and Ohio, also occurs in the Upper Coal Measures of Sebastian county, 

 8 N., 33 W., section 13, and on Poteau mountain, Indian Territory. 



Macrodon tenuistriutus Mt'vk and Wortheu, Proc. Clncitijo Ac. Sc., i. j). 17. 

 Area striata Geinitz, Carh. u. Dyas in Nebraska, p. 20, PI. i. Fig. 

 32. Macrodon tenuistriatus M. and W., F. B. Meek, U. S. Geol. 

 Surv. Nehraska, p. 207, PI. x. Fig. 30. 



This is a characteristic LTpper Coal ^Measure species, being found in 

 that horizon in Nebraska, Illinois and Iowa ; it is (juite common in the 

 Upper Coal Measures of Poteau mountain, Indian Territory. 



Macrodon sp. 



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



