TABLE OF CONTENTS. XXXV 
6. Greenstone and dykes .... 532 
Hornblende rocks analogous to greenstones . 533 
Associated with magnetic oxide of iron. 534 
(B) . Primary rocks of Orange and Rockland counties. 534 
General description. 534 
1. Granite. 535 
Locations for quarries. 535 
Veins of granite. 536 
2. Sienite and localities. 536 
3. Gneiss, description of its extent... 537 
Quarries. 537 
4. Mica slate.T... 538 
5. Augite rock, its associates and localities. 538 
6. Greenstone, varieties.. 539 
Dykes and localities... 540 
Hornblende rock. 541 
7. Quartz rock... 541 
8. Serpentine rock. 541 
(C) . Miscellaneous remarks on the Highlands and on New-York and Westchester counties 542 
Local details along the shores. 543 
Stony point. 546 
Colaberg and Buckaberg. 546 
New-York and Erie railroad.547 
Forest of Dean, Fort Montgomery and West-Point. 547 
Dutchess county. 548 
Blackwell’s and other islands. 548 
Westchester county. 548 
Putnam county. 549 
Constitution island. 549 
(D) . Primary rocks of Saratoga and Washington counties... 550 
General remarks.. 550 
Axis of elevation. 558 
(E) . Ores of the Highlands, and of Saratoga and Washington counties. 559 
Magnetic iron ores. 559 
(a) . East of the Hudson. 559 
Local details. 560 
(b) . Of Rockland and Orange counties. 565 
Local details .. 565 
List of minerals of O’Neil mine. 573 
(c) . Of Saratoga and Washington counties. 575 
Local details. 576 
Geol. 1st Dist. 9 
