2/6 J. C. BRANNER 



Attention is directed to the peculiar nature of some of the 

 great beds of Saline county ; there the strata are composed of 

 rolled or waterworn lumps as large as one's head which, when 

 broken open, show the same pisolitic structure as that found at 

 other places. It looks as though the material had been depos- 

 ited in water near the shore, and that it had been partly uncov- 

 ered at low tide or broken up by storm waves, and that its 

 earthy material had been broken and rolled by the waves, and 

 finally left at or near where it had originally lain. None of 

 the beds examined show the lamination or thin bedding planes 

 so characteristic of sedimentary rocks. 



These facts seem to point to an origin for bauxite very sim- 

 ilar to that of calcareous pisolites, and its association with the 

 syenites suggests that the latter have something to do with the 

 matter. I am of the opinion that the explanation offered by 

 Coquand, Auge, de Rouville,^ Virlet d'Aoust,^ Daubree,^ and 

 Hayes is the correct one so far as hot waters are concerned, but 

 I am unable to see why they should have been geyser waters. 

 Auge has cited* from Hayden's report of 1878, Part II, p. 416, 

 what he considers a case of bauxite actually forming in a gey- 

 ser. This, however, is a mistake ; I have examined in the 

 United States National Museum the material referred to ; it has 

 no resemblance to bauxite, and Professor George H. Merrill 

 tells me that it is a geyser mud or kaolin mechanically churned 

 up by the water and from which the silica has been removed. 

 Strangely enough this error has been extensively copied and is 

 found in many of the papers on bauxite, even as late as that by 

 M. Lauer published in 1895. 



Dr. Genth holds that the bauxite may be derived by hydra- 

 tion from corundum, but frankly admits that he cannot explain 

 the transformation. s 



■ Bull. Soc. Geol, de France, 1867-8, XXV, 935. 



^Op. cit., XV, 199; XXII, 418-420. 



30p. cit, XXVI, 915. 



-i Bull. Soc. Geol. de France, 1888, XVI, 345-350. 



5 Proc. Am. Phil. Soc. Vol. XII, 373 and 405. 



