54 
particularly deserving of notice. I visited It in company with Dr. 
Horton during the last summer, and with some difficulty we succeeded 
in obtaining specimens of considerable interest to the mineralogist. 
These are, arsenical pyrites of a silver white colour, occurring in a vein 
in the white limestone, and which I found to be composed of arsenic, 
sulphur and iron. Associated with this is the arseniate of iron, or cube 
ore, as it is called from the primary form of its crystal, which here 
occurs as a coating, and possesses a beautiful green colour and an ada- 
mantine lustre. Every where investing the two precedmg minerals is 
a powder of a lemon yellow colour, which is ascertained to be the sul- 
phuret of arsenic or native orpiment. In another part of the same 
vein is found a considerable quantity of the red oxide of iron, which, 
together with the sulphuret of arsenic, has undoubtedly been produced 
by the decomposition of the arsenical pyrites. And in addition to these 
metallic minerals, we have also arragonite in delicately radiated fibres, 
and of a snow white colour, and occasionally thin laminae of transpa- 
rent sulphate of lime or selenite. On the whole, this is one of our 
most interesting localities, not only on account of the minerals which 
it affords, but of the apt illustration which it presents, of the changes 
produced in the mineral kingdom through the influence of chemical 
agencies. 
I have thus given a general view of the Mineralogy of the State of 
New- York, chiefly in reference to its application to the arts. My object 
has been to excite an interest in this subject among the great body of 
our citizens, and to satisfy them of the utility of the work in which 
I am now engaged 5 and if I have been at all successful, I shall feel 
greatly encouraged in carrying forward these investigations to their final 
completion. 
I have the honor to be. 
Your obd't serv't, 
LEWIS C. BECK. 
January 26th^ 1839. 
