640 GEOLOGY OF OHIO. 
road crosses Black Lick. The stone has been quite extensively worked 
here. It can also be seen in various neighborhood quarries in Plain and 
Mifflin townships in the banks of Rocky Fork and Big Walnut Creeks. 
The Black Lick section is much heavier than either of the others, and 
will alone be considered here. 
It measures forty-eight feet. Its lowest bed belongs to the Waverly 
shales, but this course is seldom reached in the operations of quarrying. » 
The annexed wood eut gives the divisions of the system as it is here 
exhibited. It will be seen that the courses marked as valuable are 
quite widely separated and constitute but a small proportion of the 
quarry. Only those courses that furnish stone in blocks adapted to cut- 
ting have been thus designated. Much of the remainder furnishes 
building stone, the quality of which is quite equal to the cutting stone, 
excepting only in the size of the blocks in which it is raised. The 
waste, however, is considerable. It includes concretionary masses in 
which no bed lines can be seen, but which look like masses of mud to 
which @ rolling motion had been given before they were solidified. 
These courses are most numerous near the bottom of the system, and 
are characteristic of the lower Waverly throughout central and southern 
Ohio. Some of the best cutting stone is found in portions of the courses 
that are marked concretionary. Their courses of shale contribute also 
to the waste, but the largest element is thin-bedded sandstone that has 
little strength andas little durability. Itis light yellowish incolor. The 
layers are from one to four inches in thickness. The presence of so 
much useless material would render the quarrying quite expensive if it 
were carried on to any great extent. 
The best of the courses are, in color, light blue, and quite uniform in 
texture, and work well under the saw. The Ohio Institution for the 
Blind is built of stone from these quarries. The foundations of the 
Union Depot at Columbus were also supplied from Black Lick, as well 
as several fronts of newer blocks in the city. Like the rest of the lower 
Waverly, these quarries furnish some unreliable stone distributed through 
the best of courses. No selection is possible in the process of quarrying 
by which the perishable portions can be separated from the more durable. 
The element of time must necessarily come in, and the stone should 
never be laid until the quarry water has all escaped, for the exfoliation, 
which disfigures the surface of these treacherous portions, is generally 
connected with the escape of this quarry water. The Waverly of cen- 
tral and southern Ohio is less silicious in composition than the northern 
Ohio stone of the same age, and it is in connection with the aluminous 
constituents which replace a part of the sand that this uncertainty of 
quality comes in. 
