436 
DESCEIPTION OF PLATES. 
PLATE VI, 
Fig. 1, is a section of the west side of Lake Champlain, extending from Whitehall to St. Johns. It 
exhibits the position of all the rocks between these places. The primary upon the section marks the 
•termination of the great ranges of mountains which come from the southwest. 
Fig. 2, is a section from St. Johns to La Prairie. It is mostly level. It passes over the Loraine 
shales. 
Fig. 3, is a transverse section, or an east and west section from Lake Memphremagog to the St. 
Lawrence river, nearly on the latitude of 45°. In New-York, it passes over the northern slope, and 
is underlaid mostly by the Potsdam sandstone. 
PLATE VII. 
The sections of this plate are all transverse, or east and west sections, parallel with Fig. 3, Plate VI. 
PLATE VIII. 
Sections illustrating the geological structure of Essex county. 
Fig. 1, is nearly upon the travelled road from Crown-Point Landing to the Old Fortress. 
Fig. 2, lies upon the lake shore. It is intended to exhibit the position of the porphyiy, and the uplift 
of the Chazy limestone, south of the village of Essex. 
Fig. 3, is an cast and west section. 
Fig. 4, extends from Split-rock about three-quarters of a mile west, embracing one of the porphyry 
beds, and terminating with Trenton limestone. 
Fig. 5, is a section from the mouth of the Ausable river to Trembleau point at Port Kent, where the 
tertiary rests upon the Hypersthene rock and Potsdam sandstone. 
Fig. 6, shows the relations of the porphyry and Utica slate. 
Fig. 7, shows the uplift at Essex village, together with the remarkable undulations and fractures in 
the upper part of the Trenton limestone. 
PLATE IX. 
Section illustrating the geological structure of St. Lawrence county. 
The sections pass over a country in which the rock is very much concealed by drift and boulders. 
No rock higher in the series than the Calciferous sandrock, appears in any part of the county. To¬ 
wards the primary region, boulders become larger as well as more numerous. 
Figs. 3 and 4 may be considered as one or two distinct sections, as the line is continuous from Nichol- 
ville to Massena. 
PLATE X. 
Sections illustrating the geological structure of Jefferson county. 
Fig. 1, is a section extending from Watertown southeast to Loraine. The rocks passed over are the 
Birdseye, Isle la Motte marble and. Trenton limestone, all of ivhich appear in the bank of the river at 
Watertown, The series on this section terminates at Loraine, in the shales of Loraine, and the Grey 
sandstone. Dip S.W. 
