2(3 THE CLAYS OF AKKANSAS. 
POTTERY CLAYS. 
By pottery clays is here meant such as are commonly used in the 
manufacture of crocks, jars, jugs, and churns at the potteries now 
in operation, and not the poorer kaolins that might be used for similar 
purposes. All the clays of the State that are or have been used for 
the manufacture of pottery are grouped here under the head of pot- 
tery clays, whether or not they are available for other and more 
important uses. The common pottery clays of Pulaski, Hot Spring, 
Saline, Clark, Hempstead, and Miller counties, and those in other of 
the southeastern and eastern counties of the State, are all of sedimen- 
tary origin and of Eocene or lower Tertiary age. They were laid 
down in nearly horizontal beds, which generally dip toward the south- 
east at a low angle, so that beds that outcrop at or near the Paleozoic 
highlands lie at depths that become greater toward the southeast. 
In nature these Tertiary deposits vary from coarse sands through 
earthy marls to fine plastic clays. Many of the clay beds contain 
impressions of fossil leaves and small sticks of wood — materials that 
evidently sank, with the clays that inclose them, to the bottoms of 
the swamps or lagoons that once covered this region. 
While the pottery clays dip to the southeast and gradually descend 
to greater depths beneath the surface, the beds do not preserve 
throughout the characters they may display at a single exposure. It 
is a well-known fact in geology that sedimentary beds may vary in 
character and thickness from one point to another; indeed, they are 
even more liable to vary than to be constant in thickness and charac- 
ter. So while the pottery clays may be of uniform thickness and 
quality toward the southeast, or may even improve in quality and 
increase in quantity, it must not be inferred that this is proved. It 
is possible that they form lenticular masses; but in any case, those 
who would prospect for pottery clays within the Tertiary area of the 
State would do well to bear in mind their structural features and 
their possible" variations. 
Although sediments are deposited in approximately horizontal 
beds, the pottery clays about Benton and elsewhere in the Tertiary 
region of the State occur as, fragmentary beds in isolated hills. After 
the Tertiary beds had been laid down they were elevated, so that 
from being soft muds and sands at the bottom of the sea or of lagoons 
they came to form " dry land." But all " dry land," or all of the crusjt 
of the earth that stands uncovered by water, is subjected to eroding 
agencies which cut it down and wash it away, leaving its surface 
scored and furrowed by gullies, ravines, and valleys. By this process 
the beds of former sediments are carried away, whether they be sands, 
gravels, or clays, while over the surface is spread out a thin covering 
of the less soluble or less oortable material. 
