e more readily and cheaply the domestic product. For this reason
it is not expected that German barite will play as important a part as
formerly in American markets,--although it can undoubtedly be put down
on the Atlantic seaboard much more cheaply than domestic barite, which
requires long rail hauls from southern and middle-western states.

GEOLOGIC FEATURES

The mineral barite is a heavy white sulphate of barium, frequently
called "barytes" or "heavy spar." Witherite, the barium carbonate, is a
much rarer mineral but is found with barite in some veins.

All igneous rocks contain at least a trace of barium, which is probably
present in the silicates, and these small quantities are the ultimate
source of the more concentrated deposits. Barite itself is not found as
an original constituent of igneous rocks or pegmatites, but is
apparently always formed by deposition from aqueous solutions. It is a
common gangue mineral in many deposits of metallic sulphides, both those
formed in relation to igneous activity and those which are independent
of such activity, but in these occurrences it is of little or no
commercial importance.

The principal deposits of barite are found in sedimentary rocks, and
especially in limestones and dolomites. In these rocks it occurs in
veins and lenses very similar in nature to the lead and zinc deposits of
the Mississippi valley (p. 211 _et seq._), and, like them, probably
deposited by cold solutions which gathered together small quantities of
material from the overlying or surrounding rocks. The Missouri deposits
are found in limestones in a region not far from the great southeastern
Missouri lead district, and vary from the lead deposits in relative
proportions rather than in kind of minerals; the veins consist chiefly
of barite, with minor quantities of silica, iron sulphide, galena, and
sphalerite. The deposits of the southern Appalachians occur as lenses in
limestones and schists.

Barite is little affected by surface weathering, and tends to remain
behind while the more soluble minerals of the associated rock are
dissolved out and carried away. A limited amount of solution and
redeposition of the barite takes place, however, resulting in its
segregation into nodules in the residual clays. Most of the barite
actually mined comes from these residual deposits, which owe their
present positions and values to katamorphic processes. The accompanying
clay and iron oxide are removed by was