GREENE COUNTY. | 671 
ness, and the principal interest in its existence here is a stratigraphical 
interest, viz., in the recognition of the constancy of the elements found 
in the expanded sections to the southward. 
It is to be identified principally by its containing a fossil known as an 
elongated form of Atrypa reticularis. On the ground of its occurrence in 
Ohio strata, a distinct designation ought certainly to be given to this 
form, for it is never found above the horizon of the West Union cliff. 
The stratum is cliffy in its structure, generally showing but few lines of 
bedding, and weathering in a rough and ungainly form. The ‘“‘ Cascade” at 
Yellow Springs reveals this formation, the water of the stream being pre- 
cipitated over it, while it in turn overhangs the easily eroded shales of 
the underlying division. The same elements—geological and physical— 
occur here that are to be found at the Falls of Niagara; and more truly 
than most waterfalls, the humble cataract here mentioned can be termed 
a miniature Niagara. 
_ This elenfent is also to be noted in Cedarville township, on the south- 
ern line. 
(d.) The fourth element is economically more important than any 
yet mentioned in the geology of the county. It is the division from 
which the building stone of the county is largely supplied. The Dayton 
stone, on account of its high degree of excellence as a cutting stone, com- 
mands too high a price for all common uses, and finds its market, not in 
the country districts, but in the cities and larger towns of the State, and 
even of adjoining States. The new Chamber of Commerce in Chicago is 
built in part of Dayton stone. For all ordinary uses the stratum now 
under consideration is the principal dependence. In the report on 
Clarke county it received the designation of the Springfield stone, and by 
this name it will here be recognized. It furnishes all the building rock 
raised at Springfield, but does not, perhaps, make the most characteristic 
formation shown there, as the cap rock from which the well-known 
Springfield lime is so extensively burned, belongs to a different division, 
-viz., the Cedarville, or Guelph beds. The reasons for this nomenclature 
were given in the report on Clarke county, and need not be repeated 
here. . 
The Springfield stone has a broad outcrop in Miami and Cedarville 
townships. It is much more largely quarried at Yellow Springs than at 
any other point in the county, but on Massie’s Creck and its tributaries 
west of Cedarville it is also quite extensively worked, and the aggregate 
product of neighborhood quarries is also large. A description of this 
stratum at any one point applies very well to all other exposures. In 
the section at Yellow Springs twenty-four feet of rock are found that are 
