THE BARITE DEPOSITS OF MISSOURI 67 



along with the other stones, largely chert. Barite was seen in the 

 surface material in wheat fields, corn fields, and meadows. In 

 many instances these surface deposits are yielding splendid re- 

 turns to the owners, who are engaged in digging and hauling the 

 barite to the market while the present high prices last. This 

 surface barite sometimes appears in masses weighing 1,000 

 pounds or more, but more commonly it is in small pieces averag- 

 ing two or three pounds, with larger pieces fairly common. It 

 differs in no way from that found deeper down. 



Character of the residual deposits. — The residual deposits 

 are the most important and extensive in the district. Probably 

 98 per cent of the production of the barite comes from them. 

 They are not all of equal value at the present time and neither do 

 they all produce the same grade of barite, but these variations in 

 production are largely the result of transportational factors. The 

 grade of the barite produced in the outlying districts mentioned 

 above is essentially the same as that produced elsewhere. Like- 

 wise, the amount of the barite in these areas is about the same. 

 In the old diggings the returns to the miner are much less than 

 they were formerly, altho these diggings are being rapidly ex- 

 tended into comparatively new adjacent areas. 



Form and structure. — Typically the barite occurs as loose 

 fragments scattered thru a deep red clay, more or less mingled 

 with drusy quartz and chert (PI. IX, A) ; or as rather large 

 masses in the disaggregated dolomite at the bottom of the clay. 

 In the Central district the residual barite is confined to the clay 

 immediately over the dolomite. It really has the form of a bed- 

 ded deposit, since the ore is widespread and is in the essentially 

 horizontal surface clays. Its structure is also that of a dissemi- 

 nated bedded deposit, as the barite is found scattered thru the 

 clay. 



This clay is almost invariably a deep red color, almost pur- 

 plish-black, in some instances, and in other places a lighter shade 

 of red. The clay is remarkably plastic. It is very fine and is 

 free from grit, in spite of the great abundance of drusy quartz 

 present. This is significant in showing that the dolomite is quite 

 free from quartz, except the drusy variety. Upon exposure to 

 the air the clay shrinks greatly. This enables the miners to read- 



