GREENE COUNTY. «675 
species grandis (Billings), but also by the still larger form, Ohzoensis 
(Meek). It cannot, however, be said that either of these forms is abun- 
dant in Greene county, but their presence has been proved by a few 
_ specimens from both the Yellow Springs and Cedarville quarries. 
The lithological characteristics of the formation in Greene county are _ 
quite marked. The lowermost ten or twelve feet consist of a massive 
rock almost destitute of the appearance of planes of stratification. When 
raised by blasting it comes out in large and ungainly fragments. In 
color it is a very light gray, and the numerous cavities, large and small, 
which are found in it, are all studded with minute crystals of lime. It 
is crowded with casts of fossils of all the groups represented in the forma- 
tion, but often the forms have been rendered obscure by partial solution, 
and nothing remains but a confused mass of the firmer parts of the 
structures. Nothing can exceed the beauty which fresh surfaces of the 
rock sometimes disclose, the faces of the fossils being frosted with crys- 
tals. The heavy bed of Pentamerus oblongus referred to in the preceding 
section is found in this part of the series. 
The most interesting series of fossils thus far obtained from any one 
locality was furnished by the quarry of Mr. John Orr, of Cedarville. 
Several specimens were yielded at this point which have been found 
nowhere else in Ohio. 2 
The upper portions consist of a very thin-bedded and fragile limestone, 
often sandy in texture, and either light gray in color or yellowish. The 
latter is the predominant tint at Yellow Springs, the former at Clifton, 
while both appear at Cedarville. This portion is no less fossiliferous 
than the lower part, and both contain the same forms, though the pro- 
portions in which the separate fossils occur vary somewhat in the two 
divisions. 
In composition, the whole formation is very nearly a typical dolomite. 
A few analyses are appended to show its constitution along the line of its 
outcrop, the range represented covering at least one hundred and fifty 
miles. The analyses were all made for the Survey by Dr. Wormley. 
No. 1. Bierley’s quarry, Greenville, Darke county. 
Ae B,D wtern ens ‘¢ Sidney, Shelby county. 
‘¢ 8. Holcomb’s “ Springfield, Clarke county. 
“« 4. Sroufe’s ‘‘ Yellow Springs, (Greene county. 
‘6 5. Trimble’s, “ Hillsborough, Highland county. 
i 2. 3. 4, 5. 
Carponatevof Times reise ieee ce ee 44.60 55.00° 55.10 54.75 54.25 
Carbonate of magnesia, .......06 sessseees 50.11 42.92 43.05 42.23 43.23 
Alumina and giromey ee crascceseee ccs ses 60 1.70 2.00 1.80 
SiliclOuUspmauce4n, coueecdsssceuscesseesee ss \ 4.60 trace 0.10 0.40 0.40 
99.31 99.52 99.95 99.83 99.68 
