ee 
me the Geological Survey of the State of Alabama. 183 
4s of which 11-85 insol. 
Silica, SS. aan ee es carbonate of soda.) 
Alumina, ; - - 548 
Protoxyd of iron, - 19-24 
Lime, - - - - ‘71 
Magnesia, - - ‘87 
Potash, - - gece - £06 
Water, - - - 8:17 
Tron pyrite, - - - 146 
99-42 
Sp. gr. of the grains =2-297, 
Another Specimen, from Gainsville, sp. gr.=2°349, apparently 
slightly altered by exposure, yielded 
ili of which 23°89 insol. 
— Bae a carbonate soda.) 
Alumina, - “ é 4-71 
Protoxyd of iron, -- 21°06 (traces as peroxyd.) 
Lime, Pa - a re 99 
Magnesia, -  - - 148 
Potash vs J ; - 396 
Water, . = i 9-79 
99:96 
The analyses of the mineral from these two localities 
very well together, and agree also, on the whole, well with the 
Tesults of Prof. H. D. Rogers* for the greensand of New 
centage of silica really belonging to the mineral be thus reduced, 
the quantity of potash present will of course be proportionally 
fig nt and thus brought nearer the amount found in speci- 
“ns trom New Jersey. 
Two fine white Porcelain Clays were analyzed. — The first, from 
above Jacksonville, gave the following results, on treatment with 
Caustic potash and sulphuric acid alternately, as recom- 
. 
iD. 
mended by Brongniart and Malaguti 
* Report on the Geology of New Jersey, p. 200, et seq. 
