PREFACE. IX 



numerous figures which are here given, from cuts prepared by Mr. Peckham of 

 New- York, will sufficiently attest the richness of our localities in this respect 

 To render this i^art of the work convenient for reference, all the figures scattered 

 through the volume have been collected in the form of tables, with the mea- 

 surements of the several angles. I should state, that in regard to the j)rojections 

 of crystalline forms, Brooke's " Introduction to Crystallography," and Hai'iy's 

 " Traite de Mineralogie," have been my principal guides. In the measurements 

 of angles, however, I have often adopted the views of Phillips, and other more 

 recent authors, in preference to those of Haiiy, for reasons which will be under- 

 stood by the mineralogist. 



As there is some difference in this respect, it may be proper to state, that the 

 scale of hardness which I have followed is that proposed by Mohs, and which is 

 as follows, viz: 1, Talc; 2, Gypsum; 3, Calcareous spar; 4, Fluor spar; 5, 

 Apatite ; 6, Adularia ; 7, Rock crystal ; 8, Topaz ; 9, Corundum ; 10, Diamond. 



The history of the progress of Mineralogy in the State of New- York, is in 

 some measure connected with that of Geology. The former science, however, 

 was cultivated here long before geology assumed the form of a distinct and im- 

 portant branch of knowledge. 



Attention was turned to the study of mineralogy in this State about the end 

 of the last century. It is to the late Dr. Samuel L. Mitchill, of New -York, that 

 the science is indebted for the first movement made in its behalf. The first and 

 second volumes of the Medical Repository, published in 1798 and '99, contain 

 " A Sketch of the Mineralogical History of the State of New-York," by that 

 gentleman, which, although meagre in its details, shows that even at tliat early 

 day the business of collecting materials upon this subject was commenced. In 

 1799, a Mineralogical Society was formed in the city of New-York, ihe first in 

 the United States. The circular address of that society was published in the 

 second volume of the Medical Repository. Dr. Mitchill was the president of 

 this association ; and, as he himself states, its object was to " arm every hand 



