Dorwin Quarry there are about eight feet of waterlime- 
stone overlying twenty-five feet of blue. At Britton’s 
Quarry, on the eastern ridge of Onondaga Valley, we have 
two layers each of blue and of drab. At Hibbard’s and 
Russel’s Quarries, both near the Britton Quarry, we have 
practically the same state of affairs as at that place. 
The blue limestone is full of fossils, while the drab is 
characteristic in being wholly destitute of them. But 
there is a compensating quality here for the geologist, for 
many of the seams of this rock are lined with the rhom- 
bohedral crystals of fluor-spar andof calcite. At Alvord’s 
Quarry, Manlius, we often find these beautiful crystals 
lining the cavities of small geodes. At other places such 
geodes are rare, the crystals being generally found in the 
seams of the rock. Occasionally calcite crystals are also 
found in the blue limestone. Many of the layers also con- 
tain a peculiar form called lignilite, or epsomite. It re- 
sembles the suture joints in the skull, except that the 
individual sutures are generally, though not always, much 
longer. 
We have found the following fossils in the Lower 
Helderberg of our county. 
Tentaculites trregularis. A pteropod found sparingly 
in the lower layers. 
Flolopea antigua. A small univalve usually about a 
half inch in height. Good specimens are rare, although 
they are common in the form of casts. The best speci- 
mens are found near Skaneateles. 
Replaced Columnaria is also abundant. It is usually 
found in large masses, and is common in all the layers. 
BRACHIOPODS. 
Spirifer vanuxenu, A small but exceedingly abundant 
fossil. 
Strophodonta varistriata. Is somewhat larger than 
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