74 UNIVERSITY OF MISSOURI STUDIES 



the dolomite, which has since been removed by solution. There 

 is no evidence that the solutions attack the barite, for it shows 

 the typical crested forms and perfectly smooth lustrous cleavage 

 faces when the clay has been removed. Likewise, the quartz 

 shows no evidence of solution. 



(4) The breccias furnish proof of the former relationship 

 of the barite and the dolomite. Where barite has cemented brec- 

 cias and they have been exposed to weathering, the dolomite has 

 been removed, leaving the sharp outline of the dolomite fragment 

 in the barite (PI. III., C). 



(5) The rudely linear distribution of the barite mines sug- 

 gests that the barite was derived from an underlying vein. The 

 "leads" are very spotty; one man may be getting out fine barite 

 while his neighbor a few feet away finds only poor material. 

 This suggests derivation from a vein. 



(6) The fact that the barite still retains the pyrite (usually 

 limonite now) or quartz on which it was deposited is evidence 

 that it was derived from the veins, for the order, whether both 

 are present or not, is always the same as in the veins. 



(7) That the barite, quartz, etc., have developed in the 

 clay is improbable for the following reasons: (a) The clay is 

 remarkably plastic and impervious; thus, the passage of solutions 

 thru it would be almost impossible, (b) The barite does not 

 show any signs of enlargement, such as inclusions of clay, or 

 changes in form from that found in the veins, (c) It is well 

 known that barium salts are absorbed by plastic clays, and it is 

 therefore unlikely that they could have migrated thru the clay to 

 the centers of crystallization, (d) It is still more unlikely that 

 the order of deposition of the quartz, pyrite, and barite would be 

 the same in the clay as in the veins. 



In this connection it is important to note that in the other 

 barite deposits in this country, in Virginia, Pennsylvania, North 

 Carolina, Georgia, New Jersey, Tennessee, and Kentucky, the 

 first deposits worked were residual accumulations in clay. Be- 

 low these surface deposits, in most instances, veins or vein-like 

 masses were found. In most of the states mentioned the main 

 production is now from these veins. In the Canadian deposits 

 veins have furnished the barite from the surface down, because 



