THE BARITE DEPOSITS OF MISSOURI 97 



placement deposits in the underlying rocks. The deposits are 

 connected with sedimentary, igneous, and metamorphic rocks. Of 

 the first, limestone or dolomite is by far the most commonly as- 

 sociated rock, altho some deposits are found in sandstone and 

 quartzite. Except for those in western Kentucky which are in 

 Mississippiati rocks and those in Triassic rocks in Virginia, the 

 deposits are all found in Cambro-Ordovician dolomites or in the 

 residual clay from them. Thruout the Appalachian region they 

 are found in the Knox dolomite; Shanandoah, Beaver Stone 

 River, and Trenton limestones ; the Eden shale ; or the Weisner 

 quartzite. In Missouri, they are in the Potosi and Proctor dolo- 

 mites principally, but also in the Ordovician formations immedi- 

 ately above. In the western part of the United States, barite ap- 

 pears commonly associated with igneous rocks. 



In Virginia, the deposits in Prince William County are in a 

 series of Triassic sandstones, shales, and limestones. The barite 

 is found as the cement of a breccia of shale and limestone. This 

 breccia is apparently a fault breccia. Diabase dikes are found 

 within four miles of the deposits. In Bedford, Campbell, and 

 Pittsylvania Counties, and also in several other counties in the 

 Piedmont region, barite appears in veins and replacements of 

 highly altered schists and other metamorphic rocks. Near these 

 mines, dikes of basic rocks and granite are found. The barite 

 deposits of southwestern Virginia are in the same region as lead 

 and zinc deposits and are associated mainly with the Knox dolo- 

 mite. 



The deposits in eastern Tennessee are also found in the 

 Knox dolomite. The workable deposits are residual, but possibly 

 the veins have been found along fault zones. They are nearly 

 vertical and are from one to six feet wide. The barite in Cooke 

 County has been followed down for 150 feet. The descriptions 

 of the deposits in the southern Appalachians are so meager that 

 nothing is known of them beyond the fact that the workable de- 

 posits are residual. Whether veins exist, or not, is not known. 



In North Carolina the deposits are largely a continuation of 

 those in the Piedmont region in Virginia. Here the barite ap- 

 pears entirely as veins in crystalline schists, gneisses, and gran- 

 ites. The veins are strong and range from one to ten feet wide. 



