DELAWARE COUNTY. 311 
the variations of color and texture due to its fossils and crystalline ten- 
dency might make it take rank as a handsome marble. The lime burned 
from the various quarries about Delhi is from this stone. Yet the quarry 
of Mr. P. Jones exposes also the upper part of the bluish limestone last 
mentioned. 
Overlying the Delhi beds is the well-known “blue limestone” of Del- 
aware county, extensively quarried and used for building at Delaware. 
This is a hard and crystalline stone, variously interspersed with bitumi- 
nous and argillaceous matter. When these impurities are wanting the 
bedding is usually about six inches in thickness, but may reach ten or 
twelve. When they are abundant the bedding becomes slaty, and the 
stone is much injured for purposes of building. These argillaceous lay- 
ers which part the bedding soon succumb to the weather, and cause the 
calcareous layers to chip out or to break by superincumbent pressure 
of the wall. Numerous instances of such defective masonry could be 
pointed out in the city of Delaware, showing the treacherous character 
of much of this blue stone. Stone-cutters will be at no pains to remove 
such shaly matter from the stone, but rather prefer to leave it, even to 
the damage of important buildings, since it gives them less labor to cut. 
The effect of the elements is much greater on this stone when it is 
placed on edge in the wall, instead of being laid as it was deposited by 
nature in the quarry. The beds of sedimentation ought always to be 
- laid horizontally instead of perpendicularly. Although this stone is 
very firm and crystalline in its best estate, 1t is yet susceptible of being 
cut into all useful forms for sills, caps, keystones, and water-tables, and 
is largely used both at Sandusky and Delaware for these purposes. Its 
dark color makes it specially adapted to foundations, where a light-colored 
superstructure is intended and to all Gothic architecture. For lime it 
is very little used, owing to the difficulty of calcination, compared to 
other accessible limestones, and the heavy sediment of argillaceous mat- 
ter that will not slack. Yet the lime it makes, although rather dark- 
colored, is said to be very strong and hot. 
The following statistics in reference to the burning of lime, compared 
- with similar statistics given in reports on Sandusky and Crawford coun- 
ties, will convey an idea of the comparative value of different formations 
in north-western Ohio for the manufacture of quicklime, and the utility 
of the close or draw kiln used in some places: 
