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Tully limestone. Fossils are characteristic, but not yet named. 
The Atrypa of the same family as the Wilsoni is only found in 
this rock. This rock is met with in many places west of Tinker's 
falls, and is burnt for lime. 
Black shale. This mass has very few fossils consisting of an Orthis, 
two Lingulas and a few other shells. It contains septaria. 
Sherburne Flagstone. Found near Sherburne, Chenango county ; 
the flags there being of the finest quality. The stones are of various 
grades of thickness alternating with greenish or olive coloured shale ; 
Fucoides resembling the stems of plants are frequent in this rock, and 
also fragments of plants like the grasses. The flagstone mass extends 
from Cayuga lake through the district. 
Ithaca group. Consisting of sandstone and shales, forming a thick 
mass, highly fossiliferous. Names not given to the fossils. The top 
part of this mass terminates in a series of thin sandstone flags with 
fucoides resembling those below the group, and which separates the 
succeeding group from the Ithaca, c 
Chemung group. This forms the narrows of the Chemung river, 
whence its name. Fossils abundant and characteristic. 
Montrose sandstotie, or sandstone of Oneonta ; this is the last or 
upper rock of the third district ; it consists of many veins of gray 
sandstone, and sometimes of red sandstone ; when weathered it ex- 
hibits a peculiar structure, to all appearance owing to the manner in 
which it was deposited from water ; in this rock we often find the re- 
mains of terrestrial plants, and sometimes they are thrown together in 
such numbers as to form a thin mass of coal, extending for a few feet, 
but only an inch or more in thickness ; this rock is found in Otsego, 
Chenango and Broome counties ; it covers the whole of the upper part 
of Susquehannah county, in Pennsylvania, and being there an abundant 
rock, and surrounding the town of Montrose, I have thought it well to 
apply its name to this rock. 
We regret that we have not been able to obtain the names of more 
of the fossils which are found with the different rocks, those we have 
given being but a fraction of the whole number which they contain. 
One of the difliculties has been the want of a suitable place to unpack 
and arrange the specimens collected. Another from many of the fos- 
