20 MINERALOGY AND LITHOLOGY. 



minerals and mineral localities, and, it is hoped, also something in regard 

 to our knowledge of them. 



The minerals will be arranged in the same order as is adopted in 

 Dana's Mineralogy. This arrangement, which is based on the chemical 

 composition of the species, is most convenient for a work of this kind. 

 By this arrangement the different ores of the same metal, and minerals 

 allied together by the uses to which they are applied, are often separated 

 from one another ; but the chapter by Prof. Hitchcock, on economic geol- 

 ogy, treats of the minerals from an economic standpoint. 



As this chapter on mineralogy is followed by a short treatise on our 

 rocks, the properties and peculiarities of minerals as rock constituents 

 are referred to under the proper heads. The microscopic characters of 

 these minerals receive attention, since these characters are now of the 

 most importance in the study of lithology. Thus, incidentally to the 

 description of our minerals, an introduction to our lithology will be 

 obtained. 



In the consideration of these minerals, it has not been considered nec- 

 essary to encumber the report with descriptions of their ordinary physical 

 and chemical properties, which can be found in any text-book ; and there- 

 fore, as a rule, nothing more than the formula of a mineral is given before 

 proceeding to the mention of its individual characters as occurring in our 

 state. The following species of minerals have been identified, and are 

 referred to in the following order : 



Native Elements. 13. Sphalerite. 



1. Gold. 14. Chalcocite. 



2. Silver. 15. Pyrrhotite. 



3. Copper. 16. Pyrite. 



4. Iron. 17. Marcasite. 



5. Arsenic. 18. Chalcopyrite. 



6. Sulphur. 19. Arsenopyrite. 



7. Graphite. 20. Tetrahedrite. 



Sulphides. Fluoride. 



8. Stibnitc. 21. Fluorite. 



9. Molybdenite. Oxides. 



10. Argentite. 22. Water. 



11. Galenite. 23. Melaconite. 



12. Bornite. 24. Corundum, 



