CRAIGHEAD COUNTY. 63 
A continuation of the Tertiary strata i:i Crowleys Ridge is given 
below, in a general record of the deep wells at Jonesboro : 
Record of deep wells at the city water plant. Jonesboro. 
Ft. in. 
Red clay (loess) 20 
Gravel, mixed with red clay 4 
Joint clay 10 
Coarse yellow sand -1 
Pipe clay 25 
Gumbo 10 
Sand, very fine on top, grading downward into coarse sand and 
gravel, water bearing 60 
Very tough gumbo 50 
Blue mud with iron concretions, extending downward to 1.200 
feet. 
CLAY INDUSTRY. 
Jonesboro and vicinity. — The brick industry of Craighead County 
is confined to the vicinity of Jonesboro, on Crowleys Ridge, where 
five plants have been established for the manufacture of wet-mud 
and dry-pressed bricks. 
The following is an analysis made from one of the brick clays 
at Jonesboro. 
Analysis of brick earth from the surface at Jonesboro. 
[Dried at 110°-115° C. Brackett & Smith, analysts.] 
' Silica (Si0 2 ) 79. 49 
Alumina (A1 2 3 ) 8. 71 
Iron (Fe 2 3 ) 3.43 
Lime(CaO) j 
Magnesia (MgO). [(by difference) 2. 10 
Alkalies J 
Manganese (MnO) 2. 44 
Loss on ignition 3. 83 
100. 00 
Air-dried sand in air-dried clay 33. 40 
Jonesboro Brick Company. — One of the largest plants in the State 
is that of the Jonesboro Brick Company, where soft-mud and dry- 
pressed bricks are made. The machines for molding the two kinds 
of bricks are placed under the same shed and run by a central power 
plant. 
The clay used for the dry press is loaded into carts at the pits by 
hand and drawn to the dry shed, where it is permitted to remain for 
months before it is made into bricks. When sufficiently tempered 
it is molded into bricks and set in the kiln. The capacity of the ma- 
chine is 20,000 bricks a day. The bricks are burned in stationary 
up-draft kilns ; and it requires twelve to fourteen days to burn them. 
