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[Assembly 
shells and plants which exist in the immediate vicinity. In the tufa 
we find not only perfect unaltered shells of the most delicate spe- 
cies, but beautiful impressions of leaves from the neighboring trees, 
and even the trunks of trees replaced by carbonate of lime. One 
of these, near the village of Chittenango, has acquired some noto- 
riety, and visiters usually carry away specimens. Very fine mas- 
ses, enclosing land shells in abundance, may be obtained in the 
bank of a rail-road in the immediate, vicinity of this petrified tree. 
In this region of limestones, tufa is seldom used except for con- 
structing fences and underpinning houses. It may be used to ad- 
vantage for burning into lime, when pure and stony in its texture. 
Upon Nine Mile creek, in the county of Onondaga, the earthy va- 
riety occurs, and also the more compact. The soil along the creek 
is of a highly calcareous nature, and the hills on each side abound 
in gypsum. 
Earthy marl occurs abundantly in many parts of our district, as 
in Montgomery county, near Canajoharie, Fort Plain, and Fonda; 
in Madison county, near Chittenango; and in Onondaga county, up- 
on Nine Mile creek and other places in its vicinity. It also forms 
the bed of Onondaga lake, having been precipitated from its wa- 
ters, and containing myriads of the univalve shells which Hve in 
the lake and its tributary streams. In one instance that came un- 
der our notice, marl was used for burning into lime, and was pre- 
ferred to limestones as the process was more speedy, and required 
less fuel. It was, previous to burning, moulded into masses of the 
size of common bricks, and then calcined in a kiln constructed 
somewhat like an oven. Lime produced from marl is not consi- 
dered equal to that obtained from limestone for making mortar, 
but is used chiefly to whiten walls, -ceilings, &c. 
Gray Sparry Crinoidal Limestone^ Sfc. 
We now come to the newest or upper strata of this formation, 
which are extensively quarried in the vicinity of Auburn and on 
Onondaga hill, near Syracuse. At the former place the upper lay- 
ers contain hornstone in such abundance as to cause the rock to 
be rejected, but the inferior layers are free from this mineral. 
Throughout the southern section- of our district are many localities 
and quarries of the blue and gray limestone. The former contains 
few fossils, and when dressed and marked by the chissel, resembles 
at a short distance the eastern granite. It is wrought at ihe. state 
