OF ARKANSAS. 21 



texture is fine, and forms a plastic mass with water. Its composition is 



shown by the following chemical analysis: 



Moisture 01.10 f Silica G9.7 



Insoluble siliceous earth* •• 80.75 -^ Alumina tinged with oxide of 



iron 19.0 



Oxide of iron 3. SO 



Lime .38 



Magnesia .33 



Potash .15 



Carbonic acid 1.00 



Chlorine .GO 



Phosphoric acid ■> .075 



Water of hydration (not dri- 

 ven off at 300 deg. F.,) 



trace of ammonia and loss 3.255 



Lime .2 



Magnesia .1 



Potash .7 



Soda .05 



89.75 



100.000 



This clay contains 4.79 per cent, less alumina than the Hickman county 

 clay belonging to the same geological era; about 0«701 per cent, less lime, 

 and 0-34 less alkalies. It will, therefore, make a whiter ware, be less 

 fusible, and less liable to crack. 



I have manufactured small crucibles out of this clay, and find that it 

 produces an excellent and strong article. The moulded clay is not liable 

 to crack in drying, without addition of silica or siliceous earth, nor during 

 the burning; and the crucibles manufactured therefrom resist sudden 

 changes of temperature without cracking. The burnt biscuit ware is even 

 rather lighter colored than the original clay, which is of a very light cream 

 color. It resists fusion at a high temperature. 



Besides being valuable for the above purposes, this clay would, proba- 

 bly, be found of excellent quality for modelling, and various other uses; it 

 is, therefore, well worthy the attention of the potter and the artist. 



The section at Chalk Bluffs, does not extend low enough to enable the 

 observer to see what underlies this clay; but from the position of beds of 

 clay of, apparently, the same age, found in other western and southern 

 states, it is probably inter stratified amongst the orange and ferruginous 

 sands, that are subordinate to the shell marls, which constitute the upper 

 member of the quarternary; occupying, therefore, the same geological 

 horizon, as the white clays at the base of the section described in the first 

 volume of the geological report of Kentucky, on pages 20, 21 and 22 of 

 that volume, and the corresponding clays which, I understand from Dr. E. 

 W. Hilgard, geologist of Mississippi, are interstratified in the "orange 

 sand," of the state of Mississippi; on this account it is probable that ferru- 

 ginous, orange-colored sands occur in this part of Arkansas still beneath 

 this clay; but concealed from view under the drainage of the country. 



