OF DENISON UNIVERSITY. 
73 
Platyostoma Niagareiise is not unfrequent. Glabellae and pygidia of 
two species of Illcenus, are abundant, as are also various shells, corals, 
&c. The fossils are not equally distributed. Thin courses of rock 
are not apt to be very productive. In the thicker interspersed layers, 
however, which show external signs of fossils, considerable numbers 
are frequently developed by breaking the stone. Throughout the 
Clinton Group the fracture is irregular, and it is very difficult to ob- 
tain entire specimens. It is rarer still to obtain specimens completely 
loosened from the rock, as one or the other face is apt to be insepara- 
bly connected with it. 
DAYTON LIMESTONE QUARRIES. 
South of Dayton a continuous series of quarries extends from 
Beavertown to a poiht about a mile and a half northeast* of the Insane 
Asylum. Some of these have been abandoned, but in those now in 
operation the Dayton and overlying strata of the Niagara are shown 
in section, and small exposures of the Clinton are not infrequent. 
As a means of comparison with the district just described, a section of 
one of these quarries is given. 
Huffmaiis Quarry, {Section V.) 
About three quarters of a mile towards the southeast of the Asylum 
for the Insane, is a quarry, belonging to Mr. W. P. Huffman, of Day- 
ton. A single section of the Clinton Group is said to have been ob- 
tained here, while constructing a drain. The strata were 13 feet 
thick ; the color is light pink, and its fossils are rather few. The Ni- 
agara Group consists of the Dayton limestone, and a few layers of 
“blue cap.” The Dayton limestone consists of a 20 in. course of 
stone, surmounted by a 26 in. and a 7 in. course. The 20 in. course 
separates into a 12 in. layer, succeeded by two 4 in. layers. The 26 
in. course, even more readily, is divided into a 20 in. and a 6 in. layer. 
The 20 in. layer is naturally the most profitable, and is quarried in 
large slabs. The blue cap begins with a 10 in. course of poor quality, 
followed by an 8 in. course, still more inferior and often broken. 
Above this, iS in. or more of thin slabs, usually in small pieces, may 
be found. The color of this blue cap is denoted by its name ; its 
commercial value is destroyed by its poor weathering qualities and the 
irregular and broken condition of the stone. The quarry, therefore, 
presents four and a half feet of good Dayton limestone. The Ni- 
