112 WINCHELL AND MARCT ON FOSSILS FROM THE 



Greatest diameter of shell, .83 ; transverse diameter of whorl at aperture, .36 ; the same 

 one inch back, .22 ; dorso-ventral diameter at aperture, .30 ; depth of sinus, .22 inch. 



The total number of species thus far known from the locality is eighty-two. Of these 

 thirty-nine have been described by us, thirty-nine by others, and four are not specifically 

 determined. There are, besides, three others referred by Hall to the locality, but not 

 seen by us. 



Note. We are authorized by Prof. Hall to state that he relinquishes all claims upon our two species, follow- 

 ing, which were published by him after our paper had been read, viz : Gomphoceras Marcyce, and Acidaspis Ida. 

 A similar announcement is to be made in a postscript to his paper, on the appearance of the completed Report of 

 the Regents of the University of the State of New York, vol. xviii. 



Explanation op Plate II. 



PAGE 



Fig. i. — Cladopora lichenoides W. and M 84 



View of a portion of a frond. 



la, a, a. Ramose prolongations of the explanate portion. 

 16, b. Stumps of other branches broken off. 



jtjct. 2. — Cladopora verticillata W. and M 84 



View of one of the verticils. 



la. Place of supposed accessory stem. 

 Fig. 3. — Ischadites tessellatus W. and M 85 



Fi<r. 4. ACTINOCRINCS OBPYRAMIDALIS W. and M 87 



4a. Base of left postero-lateral ray. 

 4b. Base of right antero-lateral ray. 

 Fin-. 5. — Megistocrinus marcouands W. and M 87 



View of left side of medium sized specimen. 

 Fig. 6. — Megistocrinds necis W. and M 109 



6a. Dorsal side of a small specimen. 



66. Outline of a larger specimen. 

 Fie. 7. — Megistocrinus infelix W. and M 110 



7a. View of right side. 



lb. View of dome, showing deep sulcation on azygos side. 

 Fig. 8. — Stkophomena macra W. and M 91 



8a. Exterior of ventral valve. 



8b. Interior of same valve of a younger specimen. 

 Fin-. 9. — Strophomena niagarensis W. and M 92 



9a. Cast of ventral valve. 



96. Cardinal side of same. 

 Fi<r. 10. — Streptorhynchus hemiaster W. and M 92 



10a. Exterior of cast of ventral valve. 



106. Area, pseudo-deltidium and hinge-line. 

 Fio-. 11. — Pentajierus chicagoensis W. and M 94 



11a. Front view of ventral valve. 



116. Side view of the same. 

 Fio-. 12. — Pterinea revoluta W. and M 95 



Exterior of portion of right valve. 

 Fig. 13. — Edmondia Nilesi W. and M 97 



13a. Exterior of right valve. 



136. Cast of left valve, showing muscular impression. 



13c. Hinge-line of cast of a right valve. 

 Fig. 14. — Conocardium niagarense W. and M 97 



