60 NEW YORK STATE MUSEUM 



persistence of deposition of graptolitiferous shale no doubt exists in the 

 whole Levis basin from New York to the mouth of the St Lawrence. 



Remaining for the first on this continent we find that the shales of the 

 novaculite region of Arkansas also indicate a remarkably long persistence 

 of like conditions, the graptolite zones there denoting deposition from the 

 third Deepkill zone (end of Beekmantown or Chazy) to middle Trenton, 

 or if the occurrences in the adjoining Indian Territory are taken in account, 

 even to the end of the Champlainic. A like long interval is indicated by 

 the few graptolites hitherto collected in Nevada. 



On the other side of the Pacific we find asfain in southeast Australia 

 the Champlainic represented by nothing but graptolite shales which in a 

 continuous series range from the very bottom of that system (first Deepkill 

 zone) to at least our Normanskill zone, corresponding to the whole interval 

 from the beginning of the Beekmantown to middle Trenton time, but prob- 

 ably as indicated by the presence of Dicellograptus anceps, the 

 index form of the last Champlainic graptolite zone in Europe, extend to 

 the very end of the Champlainic, or even into the Siluric (D iplograptus 

 palmeus). 



Still more striking is the long persistence of the deposition of grapto- 

 lite shale in certain regions of Europe. In southwest Scotland and the 

 adjoining Lake District of England an immense deposition of shales has 

 taken place, which in this little extensive area in the Skiddaw, Glenkiln and 

 Moffat (Hartfell and Birkhill shale) series have afforded a system of grapto- 

 lite zones equivalent not only to the entire Champlainic (Ordovicic) from its 

 very beginning, but also, to the Lower and Middle Siluric, or to the time 

 interval from the base of our Beekmantown to the beginning of our Salina age. 



This same striking phenomenon repeats itself in Scania where in the 

 lower, middle and upper graptolite shales of the Champlainic and the 

 Rastrites and Cyrtograptus shales of the Siluric we meet an enormous 

 development of graptolite shales but little interrupted by bands of lime- 

 stone, that in time again extends from the base of the Champlainic to the 

 middle of the Siluric. 



