148 
[Assembly 
those of gi-eater breadth extend often to great distances. The 
silver vein at Guanaxuato, has been worked to the extent of more 
than eight miles, and is from 40 to 50 yards in thickness. Some 
other veins, in South America, have been traced more than eighty- 
miles. 
We find, from experience, that certain metals and minerals are 
associated with certain rocks, or are found in particular strata; 
thus, we are able, from the particular mineral association of one 
place, to predict, from a partial knowledge of another, what will 
be found. Where a bed of metallic ore, or mineral substance, ex- 
ists, it may be expected to continue through a considerable tract of 
country; or, at least, as far as the same geological formation ex- 
ists, we may expect the same metal, or mineral,'in greater or less 
quantities, yet sometimes the direction of the bed, or vein, may 
be changed, or it may disappear entirely. 
It remains only to mention, at this time, the different rock for- 
mations in the northern part of the State, and in connexion, to 
name the metals usually found in them, in the hope that many per- 
sons will abandon useless search, and others be directed aright in 
searching for ores in this region. 
Granite is the most abundant rock in this district — as before ob- 
served, it appears to form the mass of many of the mountains in 
Warren, Essex, Clinton, Franklin, Hamilton, and, to some degree, 
in St. Lawrence county, though its external characters are ex- 
tremely different in different places. Granite is the least metalli- 
ferous of the primitive strata, though it yields tin and iron, the lat- 
ter often in considerable quantities, and in this region, in very ex- 
tensive beds. Gold and silver have been found in granite in small 
quantities, in some parts of the world. 
Gneiss is considered, by some geologists, as immediately over 
granite, but it does not always appear to be the case. This rock 
is extremely rich in useful metals; most of the mines in Saxony 
and Bohemia, are in gneiss mountains. In the vicinity of Frey- 
burg, more than two hundred veins of silver, lead, tin, copper and 
cobalt, have been worked. The silver mines in Koningsburg are 
in this rock. Although gneiss is abundant in the United States, it 
is not found to be so eminently metalliferous as in Europe. 
