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DESCRIPTION OF PLATES. 
PLATE V. 
Coast section of Lake Erie, from Black-Rock to one mile southwest of Sturgeon point. This section 
shows the succession of strata from the Corniferous limestone to the Hamilton group, with the lower 
members of the Portage group. 
Note. —The figures below the section in this and the following plates indicate the distance, in miles, from Black- 
Rock or the outlet of Lake Erie. 
PLATE VI. 
Coast section of Lake Erie, continued from near Sturgeon point to the Lighthouse point at Dunkirk 
harbor. The rocks exhibited in this section belong entirely to the Portage group. 
PLATE VI a. 
Coast section of Lake Erie continued, from Van Buren harbor to Chautauque creek. 
PLATE VI b. 
Coast section of Lake Erie continued, from Chautauque creek to the Pennsylvania line. No rocks 
appear upon the lake shore higher than the Portage group, but by ascending a few miles from the 
lake shore the rocks of the Chemung group appear, and to these succeed the conglomerate, as seen 
in the section across Chautauque county. 
PLATE VII. 
Section across the formations from Lake Ontario to the northwest extremity of the bituminous coalfield 
of Pennsylvania, along the line between the third and fourth geological districts. The order of 
succession of the strata from the Medina sandstone to the coal formation is very clearly exhibited in 
an almost continuous natural section. 
This section was intended for the Report of the Third District, but being engraved too late, was left by Mr. 
Vanuxem for the present report. 
PLATE VIII. 
Section of Lake Erie shore one quarter of a mile in length, showing broken strata and intermingled drift. 
The explanation accompanies the engraving. Numerous examples of this kind along the lake 
shore show the effects of that tremendous force which has broken up the solid strata and moved 
them southward. The motion of these fragments, with gravel and sand over surfaces still undis¬ 
turbed, produce all the phenomena of striae and grooves which are often attributed to other causes. 
