42 
The concretions are also to be seen in the overlying Corniferous. 
Near the fault line the overlying layers of limestone are brecci- 
ated. The cementing agent is calcite with some fluorite crystals. 
On the Murry farm, one-half mile east of the Onondaga Cas- 
tle hotel, the sandstone occurs near the roadside, just south of Mr. 
Murry’s house. The stone is twenty inches thick. The black 
concretions are present in the lower part. The rock is full of fos- 
sil casts. ‘The Onondaga above contains many black nodules, 
some of which are eight inches in diameter. 
The underlying Helderberg is entirely composed of the char- 
acteristic fossils, Stromatapora concentrica and S. rugosa. 
At the Dorwin Springs outcrop, five miles southwest of 
Syracuse, the Oriskany sandstone is about seven feet thick. It 
has been described by P. F. Schneider in his ‘‘Notes on the Geolo- 
gy of Onondaga County’’, and is also mentioned by Vanuxen in 
the State report for 1842 and by E. B. Knapp in “ Glimpses of 
Geology of Onondaga County,” 1886. 
On the Crossett farm, four miles south of Syracuse and one 
mile north of Dorwin Springs, this rock again occurs. The ex- 
posure is near the top of the Valley ridge, along which it extends 
for three hundred yards, forming with the Onondaga a ledge 
which can be seen from the valley road quite distinctly, thus con- 
stituting a feature in the topography of the region, which is a 
rare thing for the Oriskany. ‘The rock is first seen on the south, 
in a shallow ravine. At this point it is twenty-seven inches thick. 
There are many shades of color, but it is generally lighter than 
at Dorwin’s. Fossils are rare. 
The Onondaga above is quite sandy in the lower four inches, 
with many black nodules. 
At a distance of 450 feet north of the ravine, the sandstone 
layer has gradually thinned out to thirteen inches. Going north 
300 feet further, it has entirely dissappeared excepting the four 
inches which adhere to the Onondaga and as stated, this is 
mostly composed of black concretions. Thus the seven feet of 
sandstone at Dorwin’s thins out to nothing on a north and south 
line not over a mile and a quarter in length and this is a very 
gradual diminution in thickness. The strata dip very uniformly 
