LOCALIIES OF SUPERPOSITION. 
201 
66 . 
The base line of the above wood-cut represents the surface of the corniferous limestone. 
No. 1. The lower part of the Marcellus shales, with its interrupted beds of impure limestone and shale 
with fucoids, etc. 
No. 2. The upper part of the same mass; no real line of division existing between it and the next one. 
No. 3. The lower portions of the Hamilton group. 
There are many other points along the long line of the Marcellus shales and the Hamilton 
group, where the two also may be seen passing the one into the other, but none so satisfactory 
as the one above given. 
On the east side of Cayuga lake, there are many points where the junction of the Hamilton 
group with the Tully limestone, and of the latter rock with the Genesee shale, and the slate 
with the Portage group, are perfectly seen in juxtaposition, affording every evidence and 
facility necessary for geological sections. There being no time to prepare them for this report, 
and as the whole of this series exists on the west side of Cayuga lake, and with repetitions 
along the parallel lakes of the fourth district, the large and detailed sections omitted in this, 
and which are common to the third and fourth districts, will be supplied by Mr. Hall. The 
large section upon the map, however, shows the succession of the rocks in question, and to it 
the reader is referred. The section passes by the east side of Cayuga lake. 
67. 
No. 1 of the above wood-cut represents the upper part of the Hamilton group, which exists near Ludlow- 
ville; the section passing along the lake in front of the village, the latter represented by a house in 
the gorge or valley. 
No. 2. The Tully limestone, the village in part being placed near its level. 
No. 3. Genesee slate. 
No. 4. Portage group, or shales and flagstones of Sherburne. 
Geol. 3d Dist. 26 
