156 The Ohio Journal of Science [Vol. XVI, No. 4,. 



rock can be split along these lines and the surfaces will show 

 hard, dry, carbonaceous material either solid in extent or in 

 patches. In the gray stone these lines are all through it, 

 while in the buff stone the few that occur are usually found 

 near the edges of the ledges. 



Third. — Carbonaceous material also occurs in the gray 

 stone in sheets. These sheets occur at the parting line between 

 the ledges, especially between the strata near the contact 

 between the buff and the gray stone. Particularly after- 

 blasting these sheets can be taken out entire as large as two 

 feet square. The average thickness is almost 1/32 inch, and 

 they are sometimes as thick as 1/16 inch. When these sheets 

 are placed in the fire they burn with an oily, sooty flame, 

 leaving a thin rock stratum. The sheets are not consumed 

 as a shingle would be, but the carbonaceous material seems 

 to burn out as if the sheet were soaked in oil. This suggests 

 that these sheets are very thin limestone layers heavily 

 impregnated with carbonaceous material. 



When these carbon dividing planes of the lower layers are 

 split they often show the obverse and reverse of the fossil 

 plant, Sphaerococcites (?) glomeratus Grabau. It is a ready 

 inference that these sheets and lines mark the beds of this 

 plant, from the decay of which they received their carbon 

 material. The objection that the lines are often noticed in 

 the buff stone where this fossil plant is not found can be met 

 by the statement that as the lines are thickest and most profuse 

 in the gray stone there would be the most natural place for the 

 distinctive preservation of the fossil. Further, the harder 

 texture of the gray stone which prevents the carbonaceous 

 material from penetrating the rock would also serve to preserve 

 the fossil plant distinctively and in its entirety. It also suggests 

 that the gray stone was built up by successive flourishing of 

 the plant and deposition of rock material. As the gray stone 

 is hard and very solid, we do not find carbonaceous material 

 other than as just stated, as it has no opportunity to seep 

 through the rock and collect in masses of "rock tar." 



The Buff Stone. — The buff stone being softer, less dense and 

 with numerous cavities, its carbonaceous material has the oppor- 

 tunity to present itself more distinctly than in the gray stone. 

 While carbon lines do occur, yet they are never in profusion 



