FRANKLIN COUNTY. 629. 
of scores, perhaps of hundreds of years. The reason why teeth are 
found so much more abundantly than other portions of the skeleton is 
that they are among the few portions that are thoroughly mineralized, . 
and consequently able to resist decay. The framework of the shark is 
chiefly cartilaginous. These facts help us to understand the origin of 
the layer in the Corniferous limestone which we are now considering. 
The fact, itself, is one of great interest. Hardly had fishes appeared in 
the seas before they took almost complete possession of them. A bone 
bed made of their remains, is one of the earliest facts in their history, 
in the European rocks, as it is in our own. 
IV. ECONOMICAL GEOLOGY. 
A few additional statements will here be made in regard to the useful 
applications of the Corniferous limestone. 
These applications are two in number, and have been already inci- 
dentally treated. The formation furnishes budding stone and lime. The 
supply in Franklin county is indefinitely great. It can be counted by 
the square mile, in areas that require very little stripping and where 
railroad transportation can be made easily available. The abundance of 
the supply is best understocd when it is remembered that the quarries 
are never less than twenty feet in depth, and that often thirty jeet of 
stone, almost every foot of it available for some purpose, lie above the 
river level. Assuming the specific gravity of the limestone to be 2.5, 
an acre, worked toa depth of 25 feet, yields 85,000 tons, and a square 
mile yields under the same conditions 54,400,000 tons, an amount which 
can be readily expressed in figures, but of which we can form no ade- 
quate conception. 
The character of the building. stone furnished remains to be described. 
Very much can be said inits favor. It is a dense, compact limestone, 
with a specific gravity exceeding 25. It is very strong and can bear all 
of the burdens which architecture demands. A number of the courses 
yield cutting stone that is, the stone lies in the courses in pieces of several 
hundred feet square and can be raised in blocks large enough to answer for 
sills, window-caps, platforms and similar uses. When the stone comes out 
in this way, it commands four times the price that building stone, i.e , the 
stone that is raised in blocks too small for such applications, brings. It 
is generally worked with sufficient ease, though some courses that are 
otherwise suitable have too large a proportion of flint. Its color is very 
satisfactory, all the shades being cheerful and pleasant to the eye, and 
sufficient variety being afforded by judicious selection. It receives 
ornamentation to good advantage, moulding and other relief showing 
