DESCRIPTION OF SECTION. 



Plate 3. 



This section, it will be seen, commences at the 

 Palisades of the Hudson River in New Jersey, 

 runs across the Hudson River, the island of New 

 York, the East River at Hellgate, and Long Island 

 to the ocean, and has nine, and probably ten, dis- 

 tinct rocks or formations, in a stretch of 20 miles. 

 1st Granite. — (Plate 3, fig. 1.) Evidences enough 

 of this rock have been seen and traced out to show 

 that it underlies the Trap formation that borders 

 the Hudson River, then opposite, on New York 

 Island, it shows itself largely, as is mentioned in 

 description of plate 1, fig. 1, marked 1, page 11 ; it 

 is also seen at Sunswick,, on Long Island, (now 

 called Ravenswood,) near the seat of the late Col. 

 G. Gibbs, in a quarry of Gneiss, crossing it in all 

 directions, both in veins and in layers. For this 

 fact I am indebted to Messrs. George and O. W. 

 Gibbs, and I have since visited the locality and ob- 

 tained fine specimens. 



2nd Gneiss. — {Plate 3, fig. 2.) This rock has 



