168 
THE SCIENTIST. 
phuret of zinc or blende and cala- 
niine, oxide, of zinc and carbonic 
• acid. 
Blende occurs in its pure state, 
the crystals of which are rhombic 
octahedrons, dodecahedrons, or in- 
termediate and imperfect forms, 
forming solid masses. It occurs 
alone, with clay or combined with 
calcite. Some of the crystals are 
very fine, having a beautiful amber 
or resinous color, clear as gems. 
The colors range from amber to jet 
black. 
Calamine has a vitreous and re- 
sinous color. It is more in demand 
than any other on account of the 
facility with which brasses may be 
manufactured from it. The above 
ores and others resembling them are 
called by the general name of jack. 
There are other ores in the dis- 
trict, one kind called clay bone or 
carbonate that is said to carry about 
twelve dollars per ton of zinc. It 
is widely distributed but so far 
there has been very little done with 
it. It is found in Lawrence county. 
The characterization of the coun- 
ties of Jasper, Newton, McDonald, 
Barry and Lawrence, usually called 
southwest Missouri, is that they are 
covered with the ever present chert, 
an impure kind of flint. This rock 
generally comes to the surface, or is 
only covered with a few feet of soil. 
.Where exposed to the weather it oc- 
curs in small, irregular fragments 
from one to six inches across with 
very sharp edges and corners. At 
greater depths it is in larger frag- 
ments. Very great irregularity 
marks the disposition of this chert 
with the regular limestone of the 
district, as the flint sometimes un- 
derlies the limestone, the limestone 
itself occurring in masses with no 
regularity of strata. The whole 
formation seems more like a deposit 
of drift than anything else. 
The limestone bears but little, if 
any mineral, but the calcite, which 
is a later formation, is intermingled 
with the lead and zinc. The min- 
eral occurs in large or small masses, 
called "pockets" or distributed 
more or less thickly through the 
gangue, or earth, flint or gravel that 
forms the surrounding ground, the 
adjacent crevices of the rock being 
frequently filled with asphalt or 
bitumen of the consistency of wax. 
The surface indications seem to 
have little to do with the position of 
deposits of lead and zinc, as it is 
found in ravines and on the prairie. 
Limestone ledges are usually 
avoided, shafts being as a rule aban- 
doned unless knowledge of the local- 
ity leads miners to believe that they 
are near the edge of the "bar" as it 
is called, when they attempt to 
reach it by drifting. It is at the 
edge of limestone bars that the 
mineral is frequently found. The 
limestone is probably the secondary 
rock, as fossils of the ammonite 
forms are sometimes found. 
It is a fine sight, though some- 
what startling experience, to be let 
down in a bucket into one of the 
well developed mines. The cham- 
