CRETACEOUS LIMESTONE. 
83 
putaw— Continued. Ft. in. 
5. Slightly fossiliferous, gray micaceous sand 5 
4. Ledge of indurate sand, slightly fossiliferous 10 
3. Greensand, containing same large oysters as No. 9 4 
2. Ledge of indurated sand 8 
1. Fossiliferous greensand to the water's edge 4 
The prairie soil of the Selma extends to the river north of Columbus, but is not found east 
of the river. From Columbus southward to the south side of McCowers Creek on the west 
side of the river the Tombigbee bottom ranges in width from 2 to 4 miles. South of this 
creek the bottom changes again to the east side, and the Selma extends to the river. 
At the mouth of James Creek the same joint clay that is seen above Columbus occurs on 
the east bank of the creek, about 10 feet above the water's edge. 
Eight miles east of Columbus, on the Columbus and Tuscaloosa road, the hills of the 
Tuscaloosa formation first appear. On the hill near the 8-mile post the highly stratified 
clay, interbedded with various colored sands, outcrops on the side of the road. 
At Steens Station the creek is cutting into the Eutaw sands. 
Where the road crosses Yellow Creek the foundation of the bridge is built on the compact 
sand, which here is of a deep-gray color and very homogeneous in character. 
One mile south of Strongs, on the Monroe and Clay county line, the Illinois Central 
Railroad has cut into the Selma clay to a depth of 15 feet. 
Eutaw sands extend west of the town of Aberdeen for 2 miles. Here the post-oak lands 
begin, and the regular prairie soils one-half mile farther west. There are no outcrops of 
the Selma from Aberdeen to Prairie Station. The first outcrop found northwest of Aber- 
deen is at Strongs. Here, as farther south, outcrops of the Selma are very few on its 
eastern edge. 
The following four analyses are of samples of limestone from various points in Oktibbeha 
County : 
Analyses of Selma limestone from Oktibbeha County. 
[By W. F. Hand, State chemist.] 
1. 
2. 
3. 
4. 
2.89 
2.33 
3.03 
2.55 
I 1.53 
1.72 
1.92 
1.96 
94.10 
94.35 
93. 60 
94. 07 
1.84 
1.82 
1.64 
2.12 
.36 
.44 
.42 
.52 
Average. 
Silica (Si0 2 ) 
Alumina (AI2O3) 
Iron oxide (Fe 2 C\3) 
Lime carbonate (CaCO-3) 
Magnesium carbonate (MgCO-3) 
Water 
2.70 
1.78 
94.03 
1.85 
.44 
The following analysis of a sample of the Selma chalk from near Okolona, Chickasaw 
County, Miss., is an old one, made by Doctor Hilgard.a Of the material reported as "insolu- 
ble," probably about two-thirds was silica, the remainder being alumina and iron oxide. 
Analysis of Selma limestone from Okolona. 
Insoluble (mostly silica, Si0 2 ) 10. 90 
Alumina (A1 2 3 ) '. 1. 96 
Iron oxide ( Fe 2 3 ) 1 . 42 
Lime (CaO) b 45. 79 
Magnesia (MgO) c 88 
Alkalies (K 2 0, Na 2 0) 57 
Carbon dioxide (C0 2 ) 35. 73 
Water and organic 2. 84 
. , V — . _ 
a Geology and Agriculture of Mississippi, 1860, p. 101. 
b Equals lime carbonate (CaC0 3 ), 81.77. 
c Equals magnesium carbonate (MgC0 3 ), 1.84. 
