56 
At one point only is the breccia to be seen in contact 
with the Utica. The contact is a brecciated one, the 
shale being broken up into angular fragments and the 
interstitial spaces being filled with a yellowish crystalline 
dolomitic material. Part of this shale has been altered to 
hornstone. The contact is not sharp, but there is a 
regular transition from the normal shale through the 
brecciated facies to the breccia proper. 
It will be noted that there has been a distinct bleach- 
ing and alteration of the limestone fragments in the 
breccia about their borders, showing that the paste of the 
breccia has heated and metamorphosed the included 
fragments. 
In addition to the ordinary inclusions, the breccia 
holds large masses of limestone which merit special men- 
tion. ‘These occur on the north-east side of the island. 
Of these, the middle exposure is lenticular in shape, and 
is cut by a dyke which has been subsequently faulted. It 
has an area of about 100 square feet. The rock is a fine 
grained, light grey, friable limestone. The north ex- 
posure is 200 feet in length, and is a dark grey, fine grained 
semi-crystalline limestone which is somewhat bituminous. 
It has been brecciated along the contact with the breccia, 
and the angular fragments have been cemented by a 
paste which differs in composition from the limestone. 
On a weathered surface this matrix stands in relief, forming 
a complicated network, which shows the most minute 
detail in structure. Immediately south of these two, 
there is another large block of granular siliceous limestone 
also embedded in the breccia. These masses of limestone 
are all highly fossiliferous and have been made the subject 
of a careful paleontological study by Dr. H. S. Williams. 
He finds the first two masses to be of the same age, the 
Helderbergian of the New York series. The block of 
siliceous limestone is later and equivalent to the Oris- 
kanian. 
An exhaustive study of the fossils discovered in the 
several masses has furnished the following list of species, 
which Prof. Williams has severally designated as the Spirifer 
arenosus fauna and the Gypidula pseudogaleata fauna from 
the diagnostic species distinguishing them. 
