TABLE OF CONTENTS. 



Page. 



Preface. 1 



CHAPTER I. 

 Of the geographical relations of the North- 

 ern Division of the State of New- York, 9 



Mountain ranges, 11 



Valleys, 12 



Table of heights of some important points 

 in the Second district, 17 



CHAPTER n. 



Some of the objects of Geology stated. What 

 was known of the geology of the Second 

 district at the commencement of the Sur- 

 vey. General views of the primary and 

 sedimentary rocks, and an outline of 



their boundaries, 18 



Primary formations of the northern divi- 

 sion of the State, 22 



Classification of the Primary rocks, , . . . 23 



1. Granite, 23 



2. Hypersthene, 27 



Varieties of hypersthene, 28 



Jointed structure, 30 



Limits of the hypersthene, 32 



Distribution of hypersthene boulders, 33 

 Clay from hypersthene, 34 



3. Primitive limestone, 37 



Igneous origin of limestone, 38 



Some effects of limestone on imbedded 



minerals, 57 



Varieties of primitive limestone, 59 



Geol. 2d Dist. 



PAnE. 



Range and extent of primitive lime- 

 stone, 61 



Quality of the lime obtained from it,. 03 



Its character as a mining rock, 64 



Simple minerals found therein, 04 



Use of limestone in agriculture, 05 



Some inquiries which follow from the 

 establishment of the theory of the 

 igneous origin of primitive lime- 

 stone, 65 



4. Serpentine, 67 



Localities of serpentine, 69 



Origin of serpentine, 70 



Mineral associates of serpentine, .... 71 



5. Rensselaerite, 72 



Origin of rensselaerite, 74 



Localities and extent, 74 



CHAPTER III. 



Stratified rocks, 75 



1. Gneiss, 75 



Dip and strike, 77 



Mountain ranges composed of gneiss, 77 



Gneiss as a mining rock, 78 



Imbedded minerals, 79 



2. Hornblende, 79 



3. Talc or steatite, 80 



4. Sienite, 80 



CHAPTER IV. 



Subordinate rocks, 82 



1. Trap, 82 



