200 THE CLAYS OF ARKANSAS, 
CLAY DEPOSITS. 
Over the whole of the valley regions of Scott County ordinary brick 
clays occur in the form of loam or buckshot clays. In many places 
this brick loam is from 2 to 6 feet thick. It is often high in iron, 
however, and the brick made of the clays containing much iron are 
likely to be covered with dark brown or black spots, and the bricks as 
a whole usually have a dark color. These clays are especially abun- 
dant in the upper bottom lands of Poteau River, from the point 
where it enters Oklahoma up to and east of Waldron. They occur 
also along Black Fork of Poteau, along Ross Creek, and in the broader 
parts of the valley of Fourche La Fave River. North of Poteau 
Mountain similar clays are found in the upper . bottoms of all the 
streams, but especially in those of Petit Jean Creek and its principal 
tributaries, and along Little Washburn Creek. 
No establishments of any kind in Scott County are engaged in the 
manufacture of clay products. 
SEBASTIAN COUNTY. 
CLAY DEPOSITS. 
CLASSES OF DEPOSITS. 
So far as the actual development of the clay manufacturing interests 
are concerned Sebastian is one of the most important counties in the 
State. This development could not have taken place, of course, if the 
geology of the county had not been favorable to the building up of 
the clay industries ; but the fact should not be overlooked that so far 
as geology alone is concerned several counties in the State are as well 
provided with valuable clays and clay shales as is Sebastian County. 
The geologic structure of Sebastian County admits of clays and 
clay shales occurring (1) as shales in place in the uplands of all parts of 
the county; (2) as residuary clays in the uplands derived by disinte- 
gration from the Paleozoic shales ; (3) as clays in the " second bottoms " 
or the elevated Pleistocene terraces that follow the general course of 
the river bottoms; (4) as clays in the alluvial deposits of the river 
bottoms. 
SHALES. 
The rocks of Sebastian County all belong to the Carboniferous, 
except the clays and alluvial deposits along the Arkansas River 
bottoms. There is but little variation in the older rocks of this 
county. They consist of sandstones, shales, fire clays, and coal. It 
has already been pointed out in the chapter on general geology that 
the sandstones and shales were originally deposited in water as hori- 
zontal beds of sediments, and that vegetation growing in marshes 
