New Species of Sponges. Mon 
3. Flaggy sandstone and shale, about 20 feet. 
4, Hard sandstone with quartz veins, 3 to 5 feet. 
5. Hard gray shales and calcareous and dolomitic bands, 
with some layers sf sandstone—800 feet or more. 
6. Apparently underlying these, and occupying a great 
extent of the shore, are black, gray and red shales and thick 
beds of gray sandstone, the latter appearing at Mt. Misery 
and Lighthouse Point, and holding the Graptolites above 
referred to. These beds must be of great thickness in the 
aggregate, but they are possibly repeated in part by faults 
and contortions. 
The sponges contained in Band 2 above, are apparently 
contined to a small thickness of the shale, but in this are 
quite abundant. They are perfectly flattened, and their 
spicules are replaced by pyrite; but in some cases they re- 
tain the outline of their form, and have their root spicules 
attached. The spicules were, no doubt, originally siliceous, 
but they have shared the chemical change experienced by 
other fossils in this bed, whereby they have lost their silice- 
ous matter and have had pyrite deposited in its place. In 
some cases, also, the pyritised spicules have been frosted 
with minute crystals of the same substance, greatly enlarg- 
ing their size and giving them a mossy appearance. This 
pyritization of spicules, once probably silicious, is not un- 
common in palwozoic rocks, and it arises from the soluble 
condition of the silica in sponges, and its association with 
organic matter, which, in some modern sponges, as in 
Hyalonema, enters into the composition of the spicule itself. 
These spicules, therefore, suffer the same change with the 
calcareous shells associated with them. 
Many of the sponges in these beds have been entire when 
entombed. Others are decayed and partially broken up, 
and there are some surfaces covered with confused patches 
of loose spicules arising from the disintegration of many 
specimens. 
Some remarks are perhaps necessary here respecting the 
appearance of sponges in different states of preservation. 
Of course the original textures of sponges are different, and 
