436 DESCRIPTION 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 a^rcat 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 Lorainc 

 shales. 



Fig. 3, is a transverse section, or an east and west section from Lake Mcmphremagog to the St. 

 Lawrence river, nearly on the latitude of 4.5°. 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 w-est sections, parallel with Fig. 3, Plate VI. 



PLATE VIII. 



Scctio7is 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 porphyry, and the uplift 

 of the Chazy limestone, south of the village of Essex. 



Fig. 3, is an east 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 Hypersthcne 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 drjft and boulders. 

 No rock higher in the scries 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 Lorainc. The rocks passed over are the 

 Birdseye, Isle la Motte marble and Trenton limestone, all of which appear in the bank of the river at 

 Watertown. The series on tliis section terminates at Lpraine, in the shales of Loraine, and the Grey 

 sandstone. Dip S.W. 



