EXPLANATION OF PLATES, 
PLATES XXXIII & XXXIV. 
Geological sketch along the right and left banks of the Hudson river. 
PLATE XXXV. 
Sketch of the High-rock spring, Saratoga springs, Saratoga county. 
PLATE XXXVI. 
Erratic blocks, etc. 
Fig. 1. Block of contorted hornblendic gneiss with granite veins, on the shore about north 
of Mr. Latham’s Hotel, on Oysterpond point, Long island. 
2, Block of hornblende slate, contorted, and containing contorted veins of red granite 
of a moderately fine grain, and a large forked vein of grey fine granite, on the shore 
north of Greenport, Long island. 
3. Block of granite in the water north-northwest of Oysterpond point hotel, with a con¬ 
torted vein of fissile hornblende slate. 
4. Block of gneiss showing on oblique lamination like some of the sandstones, near the 
shore at Wading river. Long island. 
5, 6, 7, Sketches of Snake hill, Saratoga lake, Saratoga county. 
PLATE XXXVII 
Drift. 
Fig. 1, 2, 3. Drift scratches. 
4. Granite boulder supported on pillars of crumbling limestone, at North-Salem, West¬ 
chester county. 
PLATE XXXVIII. 
Fig. 1. Section of Mount Bob in Columbia county, showing the Helderberg division: a. 
Blue limestone ; h. Grey limestone ; c. Fossiliferous limestone. 
2 . -. 
3. North end of Nuttenhook in Columbia county, showing the Calciferous group, etc. 
4. Interstratification of limestone and slate at Rider’s mills, Columbia county. 
5. The same at the Kinderhook lake quarry. 
6. Talcy slate and limestone in contact, north of Amenia, in Columbia county : a. 
Limestone ; h. Slate ; c. Contact. 
7. Red slate with green veins. 
