594 GEOLOGY OF OHIO. 
for constructions of foundations, underpinnings, and bridges in the 
vicinity in which the quarries are located. 
Almost everywhere in Holmes county there are lying on the sur- 
face large masses of rock which have been detached from the strata 
of the Coal-Measure sandstones. These detached masses supply the 
local demands for building stone, and no quarries are developed in the 
ledges. 
Near the central part of Knox county, from 3 to 7 miles northeast 
of Mt. Vernon, large masses of rock lie loose upon the surface. These 
have not been transported to their present station, but have been left 
in loose blocks on the surface by the undermining and removal of a 
portion of the soft shales that immediately underlie the stratum of 
sandstone. The quarry operations represented by Messrs. Bartlett 
Brothers are worked in these masses of sand-rock. This stone is con- 
sidered the best material for building purposes to be found in the vi- 
cinity of Mount Vernon. It is used for all general building purposes, 
including caps, sills, columns, ete., in the town and through the neigh- 
boring country. It is estimated that about 250,000 cubic feet may be 
obtained in some places from the surface of half an aere in area. ‘This 
material has been a source of local supply for about seventy years. 
The Waverly conglomerate, which is quarried near Howard sta- 
tion, is not so highly esteemed as is the stone of the Carboniferous con- 
glomerate, described above. The demand for it is principally for use 
in the construction of railroad bridges, arches, culverts, and to some 
extent for foundations and underpinnings. Some is shipped to Colum- 
bus, Ohio. The layers of stone in this quarry vary in thickness from 6 
inches to 6 feet, and blocks of any required dimensions may be ob- 
tained. It is rather soft when first extracted, but hardens on exposure 
to the weather. 
In Morrow county the Berea grit crops out, and is quarried in 
North Bloomfield, Washington, Gilead, and Lincoln townships. Its 
total thickness varies from 15 to 40 feet in different localities. The 
thin layers of its upper portion are very even and compact, and make 
an excellent flagging material. The most favorable development of 
the flag-stone occurs near Iberia. At this place the layers vary in 
thickness from 1 inch to 6 inches, but 235 inches is the most common 
thickness; the total depth of flag-stone is about 20 feet, below which 
from 18 to 22 feet of heavier layers occur. The quarries are located in 
