364 
[Assembly 
The Mohawk limestone is an extensive and thick deposit, in Lewis 
county, making its appearance near Boonville, on the river, and extend- 
ing without interruption through the county, with a thickness which 
cannot be less than forty feet. 
Near to Boonville its upper layers are even with the level of the ri- 
ver, but the rock rises from thence, attaining its greatest elevation a few 
miles below the village, exhibiting a cliff or mural edge, whilst traversing 
the county, its layers falling with the river from the point of greatest 
elevation, and from thence dipping probably to the northwest. 
In no place could I see this limestone reposing upon the primary, or 
observe what rock was under it, from the lower layers being concealed 
by soil or other extraneous materials. No rock can be seen between 
it and the primary, which we before have said forms the margin and 
bed of the river. 
The Mohawk limestone is extensively quarried near Boonville, for 
the locks of the canal. Its layers are thick, solid, with joints in two 
directions perpendicular to the layers, is easily worked, undergoes no 
change but solution, and for building purposes only inferior to the On- 
ondaga hmestone, not having the toughness of the latter. 
About half way in the series, there is an earthy drab or yellowish 
coloured limestone, which is burnt and used at Lowville for water lime. 
That it contains silex and perhaps alumine, seems certain, for when too 
much heated, its surface, I was told, fuses into a glass. Dr. Emmons 
has since informed me that sulphate of strontian has been found in it, 
which I did not see. 
The Mohawk limestone does not afford any metallic mineral, its value 
consists in furnishing good lime by burning, and a first rate material 
for building purposes. 
The "birds-eye" limestone does not occur in Lewis county, and 
by its absence causes the Trenton limestone to rest immediately upon 
the Mohawk limestone, and to form the second terrace west of the river. 
Trenton limestone. This rock underlies the villages of Lowville, 
Martinsburg, Denmark and Copenhagen. It seems to increase in 
thickness from Boonville to Copenhagen. At the latter place it must 
be 300 feet thick, showing a great increase in its progress from the 
