Portage Stages of New York. 



229 



The Pennsylvania geologists have been inclined to call the 

 upper stage Chemung,* while some of the official geologists 

 of New York have called the same rocks Hamilton, because 

 certain species of fossils more or less common in the Hamilton 

 stage occur in these rocks. At the Washington meeting of 

 the International Congress of Geologists, a series of these 

 fossils arranged in their stratigraphic order was exhibited to 

 several geologists and Dr. H. S. Williams recognized the 

 difference in age, thus proving that a careful study of these 

 faunas will enable one to separate them. 



In order to show the nature of this fauna, a list of the 

 species noted along the Delaware River above Port Jervis, 

 Xew York is given. From the Hamilton were obtained : — 



1. 



o 



3 



4. 



5. 



6 



?. 



8. 



9. 

 10 

 11. 

 12. 

 13. 

 14 

 15. 



16. 



IT. 

 IS. 

 19. 

 20. 

 21. 



22. 



23 



24. 

 25. 



Spirifera granulifera Hall (aa) 26. 



Spirifera mucronata (Con.) BilL(na) 27. 



Tropicloleptus carinatus (Con.) Hall 28. 



(aa) 29. 



Orthis Vanuxemi Hall (a) 



Chonetes coronata (Con.) Hall (r) 30. 



Ambocozlia umbonata (Con.) Hall (rr) 



Leiorhynchus nmlticosta Hall [rr) 31. 



Chonetes setigera Hall (a) 32. 



Chonetes scitula Hall (c) 33. 



Nuckospira concinna Hall (rr) 34. 



Athyris spiriferoides (Eaton) Hall (rr) 35. 



Cyrtina hamiltonensis Hall (rr) 36. 



Palceoneilo coastricta (Con.) Hall (r) 37. 



Nuculites triqueter Con. (rr) j 38. 



Palceoneilo emarginata (Con.) Hall 39. 



(rr) 40. 



Xucula bellistriata (Con.) Hall _ . .(rr) 41 . 



PaMoneilo muta HaU {rr) 42. 



PalcBoneilo maxima (Con.) Hall, .{rr) 43. 



Xucula corbuliformis Hall .(rr) 



Nuculites cuneiformis Con. _ (rr) 44. 



Goniophora hamiltonensis (Hall) Mill. 45. 



(rr) 46. 



Microdon (Cypricar delta) tenuistria- 47. 



f?/sHaU(?) (r) 



Tellinopsis subemarginata (Con.) Hall 48. 



(rr) 



49. 



PJioladella radiata (Con.) Hall 

 Ltd a diversa Hall 



.(rr) 



■(rr) 



Grammysia Msulcata (Con.) Hall (rr) 

 Cimitaria corrugata (Con.) Hall.(rr) 

 Actinopteria Boydi (Con.) Hall .(rr) 

 Modiomorpha concentrica (Con.) Hall 



--- (rr) 



Microdon ( Cypricardella) bellistriatus 



(Con.) Hall ..(rr) 



Xuculites oblongatus Con. (r) 



Grammysia constricta Hall (rr) 



Orthonota undulata Con (rr) 



Paracyclas Virata (Con.) Hall (rr) 



Orthonota (?) parvula Hall (r) 



Modiella pygmcea (Con.) Hall ...(rr) 

 Pterinea flabellata (Con.) Hall ..(rr) 



Leda rostellata (Con.) Hall (rr) 



Glyptodesma erectum(Con.) Hall.(rr) 



Hyolithes aclis Hall (rr) 



Tentaculites bellulus Hall (r) 



Coleolus tenuicinctum Hall {rr) 



Cyrtolites (Cyrtonella) piteous Hall 



(rr) 



Loxonema hamiltoniaz Hall (rr) 



Beller -option Leda Hall (rr) 



Belleroplion acutilirata Hall (rr) 



Homalonotus DeKayi (G-reen) Emm. 



.....(rr) 



Dalmamtes (Cnjphoius) Boothi 



(Green) Hall (?) . - - (rr) 



Psilophyton princeps Dn (rr) 



The fossils of the above list were all collected from expos- 

 ures along the Delaware River or the neighboring hills not 

 more than two and one-half miles above Port Jervis. The 

 age of the formation is Hamilton, although it has been mapped 

 and described as Hamilton and Genesee.f 



- For a discussion of a section in reference to this view see an article by 

 Prosser in this Journal, vol. xliv, p. 210. where the question is discussed in detail. 



f See 2d Geol. Survey Penna. G 6 , p. 194, and especially the geological map of 

 Pike and Monroe counties accompanying this report. 



