EXPLANATION OF THE PLATES. 
Fig. 12. One mile and a half below Croft’s point. A fault. 
13 and 14. - 
15. Contortions of the Helderberg limestone and cement beds, two miles above Rosen- 
dale, on the right bank of the Rondout. 
16, 17, 18, 19, 20, 21. Examples of contortion of the Helderberg limestone at various 
localities. 
PLATE X. 
Fig. 1. Slate intersected by a horizontal seam (Briggs). 
2. Curious contortions. 
3. Oblique strata of the Hudson river slate. 
4. The same, between Ancram iron-works and lead mine. 
5. The same, between Jackson Corners and Clermont. 
6. The same, forty rods east of Lewis’s landing. 
7 and 8. The same, and slaty layers interstratified with grit rocks, one mile below 
Rhinebeck landing. 
9. The same, contorted, one mile and a quarter below Rhinebeck landing. 
10. The same, a little below Rhinebeck landing. 
11. Horizontal section of contorted and folded strata, 100 yards below Lower Redhook 
landing. 
12. Contorted strata, Lansingburgh. 
13. Contorted lines in stratified metamorphic limestone, between Peekskill and Ver- 
planck’s point, Westchester county. 
14. Contortions in slate, caused by nests and veins of quartz : Hillsdale slate quarries, 
Columbia county. 
PLATE XL 
Contorted slate, to wit: 
Fig. 1. One mile and a half northwest of Cohoes falls, Saratoga county. 
2. Half a mile northwest of Visscher’s ferry Saratoga county. 
3. Two miles west of said ferry. 
4. Half a mile west of said ferry. 
5. 6, 7. Two miles east of Alexander’s bridge, Saratoga county. 
8, 9, 10, 11, 12, 13. At Saratoga lake. Snake hill. 
14. Anticlinal and synclinal axes, half a mile west of Visscher’s ferry. 
