REPORT OF THE STATE PALEONTOLOGIST 1901 669 



Hamilton fauna 

 Fcrnna of the Stafford limestone 

 This is another and higher limestone bank in the Marcellus 

 shales, but extends no farther east than Ontario county, while 

 the Agoniatites limestone goes no farther west as a limestone 

 than the same meridian. The Stafford limestone contains the 

 earliest extensive representation of the normal fauna of the 

 Hamilton stage. This is not actually the earliest appearance 

 of the fauna, for a calcareous layer just at the base of the Mar- 

 cellus shales in western New York also carries Hamilton spe- 

 cies commingled with others surviving from the Onondaga fauna, 

 but the Stafford affords a pure Hamilton fauna. The incursion 

 of this congeries in this manner is very significant; the lime- 

 stone and its contents are lost east of Ontario county, but from 

 there to the western limit of the state its course is unbroken. 

 Thus it clearly indicates that the Hamilton fauna, both in this 

 prenuncial expression and in its normal return, after its retreat 

 had been covered by a considerable period of deposition in the 

 gradually clearing Marcellus waters, entered the state from the 

 west; whether from the northwest, through the opening of the 

 shore line up through Manitoba and thence westward through 

 Siberia to the Ural Devonic sea, or up from the south, skirt- 

 ing the Devonic shore line of eastern South America, where it 

 arrived by shore from Africa and its center of dispersion in 

 Belgium and the Eifel or, again, along the assumed north 

 Atlantic land line, can not yet be determined. 



TuUy fauna 

 This fauna is essentially constituted of derivatives from the 

 Hamilton with the addition of two brachiopods of world-wide 

 distribution, Hypothyris cuboides and S c h i z o - 

 phoria tulliensis (cf . S. striatula Schloth.). The 

 former is an excellent index fossil of the lowest Upper Devonic, 

 the latter a belated newcomer of Middle Devonic habit. So far 

 as the^ special expression of the fauna imparted by these two 

 species is concerned, it does not elsewhere manifest itself in 



