280 J. C. BRANNER 



have charge of the work in this stage. The roof is likely to be 

 soft and to require lagging. Furthermore, unless discretion is 

 used in opening quarries and driving tunnels, the operators are 

 likely to have difificulty with the draining of the mines. 



THE DISTRIBUTION OF BAUXITE IN ARKANSAS. 



In thickness the bauxite beds vary greatly, the greatest found 

 being forty feet, and even in this case the full thickness of the 

 bed is not exhibited. In vertical distribution it has a range of 

 about sixty feet, lying, so far as observed, between 260 and 320 

 feet above mean tide level. This observation, however, refers 

 only to the Pulaski county deposits, no observations having been 

 made on the vertical range of the Saline county beds, which, 

 however seem to be at, or near, the same elevation. It is not 

 supposed that the exposures now known are the only ones in 

 the state, for it has not been possible to make detailed search 

 throughout the area in which the deposits may reasonably be 

 expected. The number of exposures will probably not only be 

 considerably increased, but it should be added, that inasmuch 

 as sedimentary beds overlie or have overlain some of the known 

 deposits, it is quite possible that there are others yet uncovered 

 by natural processes of erosion. 



These bed should be sought only in the areas of soft sands, 

 clays, and gravels and in the neighborhood of the eruptive 

 rocks of Saline and Pulaski counties. 



THE USES OF BAUXITE. 



Many attempts have been made to use bauxite as an ore of 

 iron, but with poor success or with no success at all. The kao- 

 linic varieties may be found available as kaolins, though I know 

 of no attempts to use them for such purposes. Bauxite has 

 been successfully used for the manufacture of the following 

 materials : 



1. Alum. 



2. Sulphate of alumina. 



3. Aluminum (the metal). 



