74 GEOLOGICAL RELATIONS OF ALABAMA CLAYS. 



brick being very durable, but not very sightly, since 

 they are likely to be spotted where the clay contains 

 more iron than the average. Occasionally, however, 

 we find as result of subsequent rearrangement by 

 leaching, concretionary adtion, or the like, these resi- 

 dual matters differentiated from each other in a most 

 remarkable way, so that beds of nearly pure white 

 clay lie alongside of beds of brown iron ore, itsielf 

 remarkably free from either clay or chert. The most 

 notable of such instances is at Rock Run where the 

 bed of white kaolin, analysis of which is given in the 

 body of this report, No. A. S., forms one of the walls 

 of a bank of limonite w'hich has for years furnished 

 ore to the furance. In close juxtaposition to the ore 

 and kaolin, here mentioned, is one of the beds of 

 bauxite for which this region is well known. Kaolin 

 beds of this residual nature are known in many other 

 parts of the State, resting upon the Cambrian and 

 Silurian limestones. Near Jacksonville, in Calhoun 

 county, at Tampa in the same county, and in numer- 

 ous other localities of similar nature, are limited 

 beds of kaolin, none of which, however, have as yet 

 been developed or worked. 



The following clays described below may be assign- 

 ed to these formations; the china clays, No. 190, from 

 near Gadsen and No. 205 from Kymulga; the fire 

 clays, No. 191 from Peaceburg in Calhoun county and 

 No. 127 from Oxanna in the same county; the stone- 

 war^ clays. No. 204 from Blount county and No. 192 

 from near Rock Run. 



In most of 'the large limonite banks of the valley 

 regions, these deposits of pure clay occur, usually 

 known as clay horses, some of them are undoubtedly 

 of sufficient extent to be of commercial value. Many 



