PREBLE COUNTY. : 407 
(a.) It is everywhere uneven in its bedding. The contrast between 
it and the overlying Dayton Stone, or the even courses of the Cincinnati 
Group beneath, is very striking. A layer of the Clinton Limestone can 
rarely be followed for a rod. The stone itself, in many instances, seems 
solid, but it lies in very flat lenticular pieces rather than in a regular: 
wall. It is on this account but little valued for building purposes where 
either of the other formations above named is accessible. 
(0.) Parts of it are sandy in texture, and render the local name of 
sandstone that is applied to it appropriate. The sand, it must be under- 
stood, however, is lime sand. 
(c.) Throughout the exposures of tite series in Preble and several 
adjacent counties, beds are everywhere found that acquire the name of 
firestone. They are sought for chimney backs and for all similar uses to 
which ordinary limestones can not be applied. The chemical composi- 
tion of the stone does not explain this peculiarity. The firestones do 
not differ from many of the other limestones of the State. They consist 
of 84 per cent. of carbonate of lime and about 12 per cent. of carbonate 
of magnesia. They can, in fact, be burned into a very fair article of 
lime, and have been so used in many localities, but they endure without 
crumbling all ordinary exposures to heat. 
Stone from the quarries of J. Halderman, Hsq., are largely in demand 
for these uses, finding market through all the Commu around Haton for 
many miles. 
(d.) The Clinton Limestone is, in all of its outcrops throughout the 
county, rich in its characteristic fossils. Favosite corals, chain corals, 
cyathophylloid or bull’s horn corals, and many forms of bryozoans are 
very abundant and very beautifully preserved. Some of these, the chain 
corals especially, can be well shown in polished sections of the rock. 
The stems and plates of crinoids or stone-lilies, however, outrank all 
other groups of fossils in the abundance in which they occur. The sub- 
stance of the rock is often composed of these fragments. But few per- 
fect bodies are to be found, but the plates most commonly met with have 
been identified as belonging to the genus, Cyathocrinus. | 
(é.) In close connection with this last-named fact, viz., that the forma- 
tion is made up of organic remains, it is to be added that petroleum 
abounds through many of the exposures in the county. Geologists are 
generally agreed that petroleum, when occurring in a limestone rock, is 
derived from the animal remains of the rock, but no explanation can be 
given of the fact that the product occurs at one point, and is wanting at 
another. Its occurrence in the Clinton limestone of the county was 
noted by Dr. Locke in the previous Geological Survey of the State. 
