624 GEOLOGY OF OHIO. 
stone in the quarry, and the accompanying section will give an idea of 
the method in which the strata of the Helderberg are arranged at_this 
point. It will be noticed that there is much greater diversity as regards 
stratification than is shown in the Greenfield quarries. 
The specimen sent to the National Museum is a light drab stone, 
somewhat streaked with red. Its material is of the same character as 
that of the other Helderberg stones—that is, a dolomite with a fine, 
crystaline, microscopic structure, and which emits a bituminous odor 
when struck with a hammer, although the odor is not so strong as in the 
case of some other Helderberg rocks. 
Allen county is almost entirely covered by limestones of the Water- 
lime or Helderberg formation, (@) and all of the quarries that have been 
considered worthy of note extract stone from these beds that is used for 
the more ordinary building purposes and for foundations and under- 
pinnings. The upper beds of the Niagara formation occur in the south- 
eastern corner of the county, and a few quarries were once opened in 
those rocks, but the building material that was extracted was inferior, 
and the production of quicklime from them was not profitable. 
Although the building stone obtained from the Helderberg is, as a 
rule, not of excellent quality, still, as it is the only accessible material, 
it is of much value. 
The stone quarried directly in Lima is an inferior building stone, 
and is seldom used for foundations above ground, but is in demand for 
the underground portions of foundations. The quarry is worked more 
to obtain stone for macadamizing than for any other purpose. It occurs in 
thin layers, and a block 6 inches thick is seldom obtained. ‘This thinly- 
bedded character renders it applicable as a flagging stone ; the bedding, 
however, is uneven. 
The material obtained from this quarry is a dark gray dolomite, 
which is quite porous in its character ; it dissolves in hot acid with very 
little residue, and the solution is found to contain only traces of iron 
oxide, which the microscope proves to exist in the state of pyrites. The 
polishing of a face upon this stone renders its fossiliferous character very 
prominent, which is not common in the rocks of this formation. The 
stone is very bituminous and gives forth a fetid odor when struck with 
the hammer. 
(a) Geological Survey of Ohio, Vol. II, Part i, p. 397: Report on the “Geology of Allen County,’’ 
