358 C. L. Fenton — The Hackberry Stage of 



"Hackberry Sub-stage" to the balance of the Hackberry 

 and the whole of the Sheffield. This division of Calvin's 

 was adopted by the Iowa Survey — of which Calvin was 

 director, — and is at present in more general use than is 

 "Webster's classification. 



When it is noted that Calvin used " Hackberry' ' to 

 designate one of the subdivisions of his "Lime Creek 

 Stage" it is naturally questioned whether or not Web- 

 ster's Hackberry was made to include substantially all 

 of the Owen, and on investigation it will be found that 

 Webster undoubtedly included all of the Devonian rocks 

 overlying the Sheffield formation and underlying the 



Table showing the divisions of the Hackberry Stage and those formations 

 known to lie below it and above the rocks of undoubted Cedar Valley age. 



Stage 



Sub-stage 



Zones 



Local Faunules 



Hackberry 



Owen 



Acervularia(30 ft. ) 

 Naticopais(30 ft. ) 

 Idiostroma (4-6^) 



Spirif er (20 ft. ) 

 Striatula (35 ft. ) 



1 Stromatoporella 

 / Hystrix 

 | Gigantea 



Cerro 

 Gordo 





Uno 











Questionable 



Sheffield Formation (90- ? ft, ) 













Possible 

 Cedar 

 Valley 



flora Formation (35- ? ft. ) 



Upper Actinostroma 



Bed. 

 Parting 

 Lower Actinostroma 



Bed. 



===== 



Unconformitv 









Kinderhook in the district where the Hackberry is known 

 to occur. It is true that he recognized at that time but 

 fifteen feet of the Owen Sub-stage, 1 but there can be no 

 doubt that he recognized at least part of the Owen, and 

 included it in his Hackberry Group. Several of the 

 typical fossils of the Owen were described or mentioned 

 by Webster — among them Pachyphyllum crassum, P. 

 eras sic ostatum, Westernia gigantea, W. owensis, and the 

 very typical species of Acervularia, which Webster at 

 that time considered to be a form of A. davidsoni. 



It is plain that whatever weight there may be in pri- 

 ority of publication is on the side of the term "Hack- 



1 At that time the Striatula Zone was not exposed to more than ten feet. 



