Peosser — Hamilton and Chemung Series. 



215 



3. Tropidoleptus ca/rmatus (Con.), Hall. (r) 



4. Aihyris spiriferoides (Eaton), Hall (?). (rr) 



XXII A 4 . At an elevation of one hundred feet, the bluish shales con- 

 taining an abundant Hamilton fauna are succeeded by greenish to bluish 

 unfossiliferous shales and thin sandstones. This zone is about seventy-five 

 feet thick and forms the bottom of the brook for some distance. 



XXII J 5 . At the top of these greenish rocks, and 175 feet above the 

 Level of Schenevus creek, are blackish to bluish, sharp argillaceous shales, 

 some forty -five feet of which occur along the banks of the creek. They con- 

 tain plenty of fossils, the following list of species having been obtained in a 

 comparatively short time : 



1. 



Spirifer granulosus (Con.), Hall. 



(<0 



2. 



Spirifer mucronatus (Con.), Bill. 



(rr) 



3. 



Spirifer Tullms, Hall. 



(rr) 



4. 



Atrypa reticularis (Linne), Dal. 



0) 



5. 



Idorhynohus multicosta, Hall. 



is 7 



(rr) 



6. 



Tropridoleptus earinat/us (Con.), Hall. 



(c) 



7. 



OJionetes muoronata, Hall. 



(rr) 



8. 



Aihyris cf. Cora, Hall. 



(rr) 





One poorly preserved specimen, resembling 



this s 





closely than A. spwiferoides (Eaton), Hall. 





9. 



JSFucula bellistriata (Con.), Hall. 



(c) 



10. 



Nucula corbuliformis, Hall. 



(rr) 



11. 



Palcmneilo constrieta (Con.), Hall. 



(rr) 



12. 



Nuoulites triqueter, Con. 



(') 



13. 



NucuUtes oblongatus, Con. 



(rr) 



14. 



Modiomorpha eoncent/rica (Con.), Hall. 



(rr) 



15. 



Sohimdus appressus (Con.), Hall. 



(rr) 



16. 



Modiomorpha mytiloides (Con.), Hall. 



(IT) 



17. 



Microdon (Ct/pricardella) tenuistriatus. Hall (?). 



(rr) 



18. 



Oyclonema Handltonim, Hall. 



(rr) 



19. 



Orthoceras crotalum, Hall. 



(rr) 



When this section was studied, the author was not positive whether the 

 top of zone A 3 should be considered the top of the Hamilton formation and 

 the abundant fossils of A 5 a recurrent Hamilton fauna in the Sherburne for- 

 mation, or whether the forty-five feet of zone A 5 should be referred to the 

 Hamilton. However, after examining the fauna of X and comparing the 

 section with the others of that vicinity it seems better to consider the top of 



