OF DENISON UNIVERSITY. 
19 
Though the conglomerates may disappear or vary, the fauna of the 
subjacent shales aiford 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 about 
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 possible to satisfactorily demonstrate 
our position, the palaeontological 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 question is 
sometimes dark and shaly, at others is dense and crystalline. Its fauna 
is quite large and the following species have been identified. 
1. Productus cora, rare, though common as at Flint Ridge. 
2. Pi'odiictus semireticulatiis, common. 
3. Productus longispiniis^ not common. 
4. Chonetes ? 7 iesoloba, rare. 
5. Athyris subtilita, common. 
6. Spirifer camei'atus^ (rzr S. striatus. ) 
7. AUorisma subcuneata. 
8. Naticopsis nodosa. 
9. Naticopsis nana ? 
I o. Macj'ocheilus ponder osus ? 
1 1 . Macrocheilus planus ? 
12. Macrocheilus paludinoeformis small form. 
13. Macrocheilus fusifonnisl 
14. Bellerophon nodocaidnatus, fine large specimens. 
14. Bellerophon sp. 
The fifteen species discriminated are beyond doubt coal-measure 
forms and the chief difference between the assemblage and that at 
