1G2 
CEMENT MATEKIALS AND INDUSTRY. 
[BULL. L'43 
United States Geological Survey by George Steigcr. The results are 
given below: 
Section of Robertson quarry, Earlham. 
Num- 
ber. 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
Dark-colored, fine-grained, pebbleless soil 
Reddish bowlder clay with pebbles and quartzite fragments 
Yellowish-colored, soft, shaly limestone, which disintegrates 
readily - 
Layer of very hard, light-gray, fine-grained limestone 
Narrow layer of softer limestone with less perfectly comminuted 
fossil fragments 
Ledge of hard, white limestone, fine-grained, separating in places 
into three or four uneven layers 
Soft, calcareous shale which weathers rapidly into fine bits 
Dense gray, fine-grained limestone; fossil fragments abundant 
but indistinct 
Gray shale like No. 9 
Layer of hard gray limestone 
Band of soft shale 
Dense, fine-grained, light-gray limestone, in places massive, 
again separating into two layers of about equal thickness 
Shale, soft, gray in color, and quite calcareous •. - 
Layer of impure limestone, grayish yellow in color 
Band of soft, gray, calcareous shale 
Ledge of hard, fine-grained, light-colored limestone, imperfectly 
separated into three uneven layers 
Massive layer, separating in places into two uneven layers with 
shaly partings between them and such partings of shale sepa- 
rating No. 3 from No. 4 above and No. 2 below 
Ledge of gray limestone 
Layer of gray limestone 
Feet. 
Inchc 
Analysis of Earlham limestone. 
Silica (SiO s ) 
Alumina (Al.,0 : .) 
Iron oxide (Fe 2 3 ) 
Lime (CaO) 
Magnesia (MgO) 
Sulphur trioxide (S0 3 ) 
10 
«1 
17 
No 
The beds above the Bethany have not been as carefully studi 
though they are apparently similar in composition and character. 1 
next higher limestones, the Dekalb, yielded the following on pan 
analysis by J. B. Weems: 
a This includes any P 2 5 or Ti0 2 present. 
