EXPLANATION OF PLATES. 
Fig. 8, Section at the north end of Nuttenhook, Columbia county. 
9. Contortion of limestone. 
10. Apparent contortion across strata on the right bank of Catskill creek, a quarter of a 
mile below Madison corners, Greene county. 
11. Contorted rocks one mile from Catskill, on the creek opposite Rouse’s tannery, 
Greene county. 
12. Contorted slate, one mile north of Snake hill, on the shore of Saratoga lake, Sara¬ 
toga county. 
13. Section at the Mineral spring three miles west of Athens, Greene county: a. Blue 
limestone; h. Fossiliferous limestone ; c. Quaternary clays ; d, Hudson slate group. 
14. Section from Kaaterskill stone bridge to Catskill, Greene county. L. Helderberg 
limestones, blue, grey, and fossiliferous ; M. Marcellus shales ; S, S'. Hudson slate 
group ; T'. Clays of the quaternary. 
PLATE XXXIX. 
Fig. 1. Redbridge lead mine, Ulster county : a. vein ; h. Arched slate at fault; c. Shawan- 
gunk grit. 
2. Section across the Shawangunk to the Redbridge coal mine : a. “ Coal mine h. 
Fossiliferous grits ; c. Limestone and Shawangunk grit; d. Lead mine. 
3. Section across the Shawangunk mountain to Port Jervis, Orange county ; a. Shaw¬ 
angunk grit; h. Red grit and slate ; c. Dark slate with double cleavage ; e. Lime¬ 
stone (Helderberg division); f. Quaternary ; g. Dark shales and grits, almost 
trappean. 
4. Bent strata next a fault on the right bank of the Delaware, four miles and a half 
below Halfway brook, below the mouth of the Lackawaxen. 
5. Quaternary and drifts ; Coxsackie, Greene county. 
6. Waterlines of deposition in the quaternary at Coxsackie. 
7. The same at East neck on Long island. 
8. The same at Eaton’s neck. Long island. 
PLATE XL. 
Fig. 1. Echelon hills of rock. (By Prof. Dewey, SillimarCs Journal, Vol. 8, p. 11.) 
2. Oolitic structure. {Silliman’s Journal, Vol. 9, p. 19, pi. 2). 
3. Contorted slate, two miles west of Vischer’s ferry. 
4. Bent slate, fifty rods below Alexander’s bridge. 
5. The same, above the bridge. 
6. Bent slate on the Mohawk river. 
7. Deposition layers, two miles west of Halfmoon. 
8. The same, three miles west of Vischers quarry. 
9. The same, half a mile east of Vischer’s. 
10. Vischer’s quarry. 
