1897.J DRAKE — THE GEOLOGY OF INDIAN TERRITORY. 405 



Productus pertenuis Meek. Final Report U. S. GeoL Survey Ne- 

 braska, p. 164, PI. I, Fig. 14, PL VIII, Fig. 9. 



Productus cancrini Geinitz. Carbon und Dyas in Nebraska, p. 54, 

 PI. IV, Fig. 6 (not Murchison, Verneuil and Keyserling). 



Tiie specimens referred to Productus pertenuis are rather larger 

 than those figured by Meek, and have somewhat stronger radial 

 ribs. But the thinness of the valves, the great convexity of the 

 ventral valve, the lack of a medial sinus, and the disposition of the 

 small spines all agree with the figures and descriptions of Meek's 

 P. pertenuis, and the form referred by Geinitz to P. cancrini M. 

 V. K. 



Adults of the shell a.verage about three-fifths of an inch wide 

 and the same in height ; convexity of the valve for a shell of these 

 dimensions is nine-twentieths of an inch. The shell referred by 

 Meek, Geol. ExpL 40th Parallel, Vol. iv, p. 78, PL VIII, Fig. 4, 

 to P. longispinus Sowerby, probably belongs to P. pertenuis, for it 

 lacks the medial sinus, and has the other characters o^ P. pertenuis, 

 except that the beak is not quite so slender. 



Horizon a?id Locality. — Lower Coal Measures, four miles north 

 of Vinita ; one mile south of Muscogee : Upper Coal Measures, 

 Cavaniol group, McClellan ford on Verdigris river ; Poteau group, 

 six miles west of South Canadian ; Permian division, upper bed of 

 sandstone four miles west of McDermitt ; Pawhuska sandstone, five 

 miles west of Gushing. The same or a nearly related species also 

 occurs in the Lower Carboniferous limestone, Boston group (St. 

 Louis-Chester), five miles southeast of Adair ; a specimen from this 

 locality is figured on PL XII, Figs. 8, 9 and 10. 



Aviculopecten rectilaterarius Cox. PL IX, Fig. 6. 



Avicula rectalaterarea Cox. Geol. Survey Kentucky, Vol. iii, p. 

 571, PL ix. Fig. 2. 

 The shell is somewhat semicircular in outline, the greatest length 

 being about equal to the greatest width. The hinge line is straight 

 and nearly equal to the greatest width. The beak is small, rounded, 

 does not project above the hinge line. The rounded anterior ear 

 is rather sharply set off from the rest of the shell, and differs 

 slightly from it in having the radial ribs rather coarser and further 

 apart. The left valve has the base of the anterior ear somewhat 

 notched. The posterior ear, which is longer than the anterior, is 



PROC. AMER. PHILOS. SOC. XXXVI. 156, 3 B, PRINTED JAN. 18, 1898. 



