80 UNIVERSITY OF MISSOURI STUDIES 



rare in the Missouri barite region; sandstone, tho more abund- 

 ant than shale, is very subordinate to the dolomite. Many analy- 

 ses of shales, sandstones, and clay were found, the average BaO 

 content being about .05%. Slates and quartzites also contain 

 barium as would be expected. Watson^ reports the unusual 

 amount of 4.46% BaSO^ in the Weisner (Cambro-Ordovician) 

 quartzite. Certainly this barite must have been introduced into 

 the rocks. 



Failyer^ studied the soils of the Great Plains and found that 

 they all contained small amounts of barium, on the average about 

 .06%. The maximum was .11% and the minimum .01%. The 

 source was traced to the feldspathic pebbles in the gravel, which 

 had been largely derived from the Rocky Mountains. Many 

 other soils were examined and almost every one was found to 

 contain barium. The exception was a highly calcareous clay. 

 This exception is worthy of note in view of the general absence 

 of barium from limestone. 



Igneous rocks almost universally contain barium. Clarke 

 gives as the average .102% of BaO. Rocks high in potash and 

 low in silica are generally high in BaO, according to H. S. Wash- 

 ington.® The amount of barium in some cases reached .80%, for 

 example, in the rocks from the Leucite Hills, Wyoming. This 

 statement is in keeping with the fact that the only important 

 pyrogenetic barium-bearing mineral is celsian, BaAlgSiaOg, which 

 is isomorphous with potash feldspar. Analyses of potash feld- 

 spar usually show some BaO. Biotite may also contain some 

 barium. Winslow® states that barium is much more abundant in 

 the igneous rocks of Missouri than in the dolomites and lime- 

 stones, but unfortunately he does not give the percentages. The 

 conclusion reached is that igneous rocks are a far more adequate 

 source of barium than any of the sedimentary rocks, especially 

 limestone and dolomite. 



•Watson, T. L, Ga. Geol. Sur. Bull. 13. 1906. 

 'Failyer, G. H., "Barium in Soils," Bureau of Soils, Bull. 72. 

 ^Washington, H. S., "Barium in the Roman Comagmatic Region," 

 Carnegie Pub. 57, pp. 188-191. 1906. 

 ^Winslow, Arthur, ibid. 



