100 CEMENT MATERIALS AND INDUSTRY. Lbull. 242 
sufficiently friable to soil the fingers, and thin pieces may be brokei 
in the hands, but the hammer is required to pulverize the massiv< 
rock. On exposure the chalk breaks into conchoidal fragments, whicl 
weather to lumps and finally become chalky dust. In the hillside 
south of town the bedding is scarcely preceptible. 
The composition of fresh chalk from the bed of the branch at th< 
base of the exposure is given in analysis No. 4 (p. Ill), while No. I 
shows that exposed in the ditches, 55 feet higher. The former is no 
many feet above the base of the true chalk and the latter belongs nea 
the middle. This chalk is in physical appearance like that of White 
cliffs, and a comparison of the analyses shows that this chalk and tha 
from Whitecliffs quarry have practically the same composition. 
The lower beds are exposed by the road in the SE. i of SE. \ sec 
21, T. 12 S., R. 32 W., also near the middle of sec. 21, with chalky man] 
cropping below. These basal beds are more clayey and siliceous tha 
those higher in the formation south of Rocky Comfort. 
From the center of sec. 21 to the "line road" in the SW. J sec. 2 
the chalk is concealed beneath residual black soil. At the latter localit I 
the chalk is well exposed in ditches and on high ground along the roa 
almost through the SE. i of SW. £ sec. 29. The lower beds of th! 
formation are also exposed in the hill and bluff facing the river bottor 
in the NE. ± of NE. i sec, 31. 
From the base of the chalk downward there is a transition zon 
of bluish clayey chalk which grades down into still less chalky clay 
This transition clay chalk is exposed at the contact in the SW. \ sec 
29, and in deep ditches on the hill slopes below the Hopson graveyarc 
in the NE. \ of NE. i sec. 30. 
Analysis No. 2 (p. Ill) is of a specimen of the transition clayey chaj 
from the latter locality. While the analysis shows that the marl cor 
tains 25 per cent of silica, sand is not visible. 
From sec. 30 northward to the Holman place, near the center c I 
sec. 18, the clayey chalk is generally concealed by its residual soi 
Grayish -blue, sandy, chalk} 7 marl, partially indurated at the surfac< 
outcrops at the Holman House and in gullies 500 feet farther wes 
This chalk} 7 marl is perceptibly more sandy than that higher in tti 
section immediately below the true chalk. 
The crumbling edges of the chalk deposits outcrop in the low blu 
of Walnut Bayou bottom from the NE. \ of NE. | sec. 30 southwai 
to the extreme south end of the chalk area, in the SE. \ of SW. \ < 
sec. 32. 
Excellent exposures of the chalk occur in and near the road in tti 
SW. \ of SW. i of sec. 32. The analysis of this chalk is given I 
No. 1 of the table. The chief difference between this and the othe 
samples of the purer chalk analyzed is that it contains much moi 
