GEOLOGICAL SURVEY OF TTIE TERRITORIES. 469 



3. Zaphrentis A small, slightly curved species, 



with fossula ventral. 



4. Michelinia Like M. tenuisepta^ Phillips' (spe- 



cies.) 



5. Chcvtetes Slender ramose species 



0. Plafycrinites {?) Arms and fragments of columns. 



7. FlatijerinHcs Haijdeni.^ IMeek.* 



8. Pentremites fiymmetricus, Hall ..As far as can be determined from 



the specimens, it seems to agree 

 well with P. symmetricus. 



9. Pentremites Godonii, Defrance (?) 



10. Poteriocrinites Montanaensis, 



Meek, t 



11. ErisocHnus (!) Body only, apparently of a species 



of this genus. 



12. PUIodictya. 



13. FenesteUa Very delicate; like F. plebeja, 



McCoy. 



14. Ptilopora. 



15. Sirophomeyia analoga, Phillips. 



16. Orthis rcsupiiiata, Martin. 



17. Chonetes .... A medium-sized, very finely striated 



species. 



18. Productus semireticulatus, Mar- 



tin, (species) A small, sulcated, strongly arcuate, 



and produced variety, apparently 

 of this species. 



19. Productus Altonensis, N. & P. 



20. Productus seahrwulns, Martin (?) 



21. Productus Prattenanus, Nor- 



wood. 



22. Productus cora^ d'Orbigny (?). ..This agrees with European shells, 



referred to d'Orbigny's species; 

 but is more finely striated, and 

 much more i)roduced, than d'Or- 

 bigny's type. 



23. Productus A narrower, strongly arched, much 



produced species, marked by 

 small, very obscure concentric 

 wrinkles, and very small, slightly 

 elongated, raised points, that may 

 have supported minute spines. 



24. Eemipronitescrenistria^PhiWijys, 



(species.) 



25. Camarophoria Very similar to C.fjlohuUna, Phillips. 



26. Athyris subtilita, Hall. 



* A small species, with a cup-shaped body, rounded below to a circular attachment 

 for the column ; body-plates smooth, or obscurely granular, and joined by slightly 

 grooved sutures; arms twenty, slender, each dividing once on the second piece above 

 their origin on the very small second radials, composed each of a single series of small 

 pieces, (as in P. nodohracliiatus, Hall, Iowa Report, p. 542.) bearing pinnules alternately 

 on their inner lateral ends. 



+ A small species with an elongate obconical body, composed of smooth plates, and 

 supported on a round column ; arms long, slender, api)arently simple abovi; their origin 

 on the last radmls, and composed of small pieces, every third one of which bears, alter- 

 nately on opposite sides, ;i long pinnule. 



