912 GEOLOGICAL RECONNOISSANCE 
indicate an infiltration of the zinc through interstices of the previously 
formed rock. Perhaps the most plausible explanation of these pheno- 
mena, is that the ore was first in the state of sulphuret, and was subse- 
quently changed into carbonate by some reciprocal play of chemical 
affinities acting from the interior upwards. The increase of the sulphuret, 
as you descend in the rocks, and the general structure of the deposits, 
which resemble inverted cones, showing a divergence at the surface from 
a central point of action; together with the existence of carbonate, of 
zinc, in the associate rocks and clay, rather favor this view of its forma- 
tion. 
It is a remarkable fact, to which attention was first called by Dr. Koch, 
that, where deposits of calamine are found at the surface, the only vege- 
tation to be seen is asmall, black lichen, closely adhering to the ore or 
accompanying rocks; and the soil, to the depth of a few inches, is of an 
intense black color. 
There are, in addition to those already mentioned, four other mines, 
opened and belonging to the Independence Mining Company, on the 
following sections, viz: Section 28, township 17 north, range 3 west; 
sections 12,28, and 29, township 18 north, range 4 west. 
At the town of Powhatan, in the street leading to Smithville, I discovered 
a deposit of carbonate of zinc, the extent of which cannot be known 
without digging; but it is no doubt considerable, and there is every reason 
to believe, that good calamine will be found abundant in the immediate 
vicinity of this town. 
Powhatan is situated on Black river, a stream navigable for small boats 
at all seasons of the year; it has under construction, and partly graded : 
plank road leading to Gainsville, in Greene county, which will rapcicces 
the Cairo and Fulton railroad twelve miles distant. This, together with 
the fact, that it is surrounded by, and close to, the main deposits of zine 
ore, renders it the most desirable point for the location of a zine smelting 
furnace. In addition to the advantages to be gained at this place for 
shipping the metallic products of the furnace, abundance of charcoal may 
‘at all times be had, from the extensive forest bordering on Black river. 
These suggestions, for the lecation of a zine furnace at Powhatan, are 
made from the fact that the “ Calamine” furnace, from nieanieament 
did not go into successful operation; and experience has shown that ‘ts 
location is not a favorable one. At all events, before the members of the 
zinc company remodel their establishment and engage experienced 
smelters, they should take into consideration the advantages of a change 
in the location of their works to Powhatan, or some equally esa 
point on Black river; because the success of the enterprise certainly 
