Weller — Kinderhook Faunal Studies. 193 



the other one* is a member of the genus 8trophostylus, but 

 is probably specifically distinct from the specimens from the 

 oolitic layer. These last mentioned specimens should be con- 

 sidered as the true types of the species. They are three in 

 number, the largest one is illustrated here for the first time, 

 and one of the others, the most perfect of all, has been well 

 illustrated by Keyes.f The third specimen is smaller than 

 either of the others and shows no characters which are not bet- 

 ter exhibited on the others. The Chonopectus sandstone speci- 

 men which is a true Strophostylus differs from the oolitic 

 specimens in having the inner whorl of the shell much thicker 

 so that the shell expands much less rapidly ; the number of 

 whorls also in this individual is probably greater than in the 

 oolite specimens although the apex of the sheU is destroyed. 



CEPHALOPODA. 



Orthoceras indianense Hall. 



PI. XVII. f. 13-14. 



A small, smooth orthocereas which has usually been re- 

 ferred to this species is not uncommon in the oolite fauna. 

 The specimens are usually elliptical in cross-section with the 

 siphuncle situated eccentrically. Specimens from the Chono- 

 pectus sands tone, t have been referred to the same species, 

 and those from the Vermicular sandstone at North view, Mis- 

 souri, which were identified as C. chemungense Swallow, § are 

 also possibly the same. 



Gyroceras burlingtonensis Owen. 



PI. XVIII. f.l. 



Original description. ** Scroll-shaped ; volutions about 

 two, rapidly enlarging; chambers forty-eight (?), indicated 

 by undulating lines curving from the inner margin of the 

 periphery." 



♦ For an illastration of this specimen see Trans. Ac. Sci. St. Louis. 10, pi* 

 V. f. 4-5. 

 t Rep. Mo. Geol. Surv. 6. pi. 53. f. 4 a-b. 

 X Trans. Acad. Sci. St. Louis. 10: 120. 

 § Trans. Acad. Sci. St. Louis. 9 2 45. 



