OF DENISON UNIVERSITY. I9 



Though the conglomerates may disappear or vary, the fauna of the 

 subjacent shales afford conclusive criteria for ascertaining at least their 

 approximate position. With these two lines of reference once estab- 

 lished, and leveled east and west through our district, the study of 

 higher and lower horizons became more fruitful. 



Before discussing the work in this field it becomes necessary to recall 

 some points already stated in the first paper. It will be remembered 

 that our attention was given solely to a thin band of shale lying about 1 60 

 feet above the bottom of the coal-measures at Flint Ridge. In the same 

 report a band of limestone is referred to as occupying a place aboul 

 100 feet above the Maxville limestone, in Muskingum county and con- 

 jecturally referred to the position of the lowest coal seam east of New- 

 ark, at Bald Hill. This limestone has been further examined, and al- 

 though it has not yet been found ])ossible to satisfactorily demonstrate 

 our position, the paljeontological evidence is not inconsistent with that 

 theory. West of Fultonham this thin band is well exposed and lies 

 about 120 feet below the coal mines of that region. If these coal 

 mines are on the same horizon as that at Flint Ridge, the relation is 

 the same as at that place, except that a few feet are interpolated (as 

 would be expected) above and below. The limestone in (juestion is 

 sometimes dark and shaly, at others is dense and crystalline. Its fauna 

 is quite large and the following species have been identified. 



1. Froductus cora, rare, though common as at Flmt Ridge. 



2. Froductus scmireticulatus, common. 



3. Froductus longispinus^ not common. 



4. Chonetcs mesoloba, rare. 



5. Athyris subtilita\, common. 



6. Spirifer camcratus, (=: S. striatus. ) 



7. Allorisma subcuneata. 



8. Naticopsis nodosa. 



9. Naticopsis fiana ? 



I o. Macrocheilus ponder osus ? 



1 1 . Macrocheilus planus I 



T2. Macrocheilus paludi/uvfonnis, small form. 



13. Macrocheilus fusiform is ? 



14. Bcllerophon nodocarinatus, fine large specimens. 

 14. Bcllerophon sjj. 



The fifteen species discriminated are beyond doubt coal-measure 

 forms and the chief difference bi-twecn the a.ssemblage and that at 



