212 CEMENT MATERIALS AND INDUSTRY. [bull. 
channel into the Selma chalk, which outcrops almost continuou 
throughout its course. The limestone occurs up the creek about 6^ 
7 miles northwest of the town of Wahalak, but the Porters Cr« 
clay occupies the country on either side of the creek. The hill j 
east of Wahalak is of Porters Creek clay, which is not over 15 i 
thick. 
A sample of limestone was collected by A. F. Crider from the II 
of Wahalak Creek, about li miles south of Wahalak. This sam 
was analyzed by W. 8. McNeil in the laboratory of the United Ste 
Geological Survey, with the following results: 
Analysis of Selma limestone from near Wahalak, Miss. 
Silica (Si0 2 ) 2i 
Alumina ( A1 2 3 ) 
I 
Lime carbonate 6 
Magnesium carbonate 
Water 
A sample of the Selma limestone was taken from the bed of Wah* 
Creek, 1£ miles south of the town, and on the range of low hill 
the south side of Wahalak Creek, 1J miles southeast of the point wt 
the Mobile and Ohio Railroad crosses the creek, another sample 
taken. 
At the top of the Selma chalk there is about 10 feet of a sand i 
cemented with lime carbonate, which contains numerous little bivs 
shells. This is the same kind of stone as that found 7 miles eas* 
Sucarnooche. There is no evidence of any Midway limestone g 
where from Wahalak to the Alabama line, and this is the only p 
where the sandstone was seen in Mississippi. 
The Midwa}^ or Flatwoods clay is well shown near Scooba, ¥ ] 
A sample collected by A. F. Crider was analyzed by W. S. McNe 
the laboratory of the United States Geological Survey. The resu 
of interest because clays of this type occur everywhere near the w 
ern edge of the Selma limestone area, and such clays will be neede 
reduce the percentage of lime carbonate found in some of the pn 
samples of Selma chalk. 
Analysis of Midway clay from Scooba, Miss. 
Silica (Si0 2 ) 
Alumina (A1 2 3 ).. 
Iron oxide (Fe 2 3 ' 
Lime(CaO) 
Magnesia (MgO).. 
Soda (Na 2 0) 
Potash (K 2 0) 
Loss on ignition... 
