38 THE CLAYS OF ARKANSAS. 
Deciper Creek, seems to be the same shale bed. Professor Harris 
has identified the Arkadelphia blue shale again on Mine Creek, near 
the old town of Nashville, where it is 4 feet thick." 
Within the Cretaceous area there are large areas covered with 
buckshot clays. These clays are not of Cretaceous age, but are much 
newer — Pleistocene and Recent— and are made of the residue of any 
clay-bearing strata that may be at hand after the decomposition of 
the underlying rocks. In the low, flat lands, commonly known as 
"slashes," thin beds of plastic clays are found at places where acidu- 
lated waters have leached the iron from the soil. Some small pot- 
teries get their clays from such places. The supply of available clays 
of this kind is uncertain, and most of the areas covered by them are 
small. Such clays occur in the flat lands of the Cretaceous, Ter- 
tiary, and Quaternary areas of the State, which, however, are not 
alluvial lands, properly speaking. 
Reference has been made to the waterworn materials that occur 
in the Tertiary region of southern Arkansas. This material is at 
some places extremely coarse, made up of cobbles the size of a man's 
head or even larger, and at others consists of pebbles no larger than 
a hickory nut. This gravel spreads over and obscures the outcrops 
of the Tertiary beds throughout the region, and is especially thick 
along the foothills on the northwestern margin of the Tertiary expo- 
sures. In thickness the deposit varies greatly, being in one place 
only a few inches and in another from 25 to 40 feet thick. In some 
places it has a tendency to accumulate in depressions; in others it 
is found in considerable quantity only on the hilltops. Inasmuch as 
the presence of this waterworn material often interferes not a little 
with prospecting for pottery clays these peculiarities of its distribu- 
tion should be kept in mind by prospectors and clay miners. 
The presence in the pottery clays of leaf impressions has been 
mentioned. A small collection of these was made and sent to Lester 
F. Ward, of the United States Geological Survey, for the purpose 
of ascertaining whether they threw any light upon the geologic age 
of these clays. Professor Ward's conclusions on this subject are 
that the beds are probably lower Tertiary, but he says that the 
specimens from the Henderson clay pit, north of Benton, Saline 
County, "have a very curious and suggestive resemblance to some 
of the Amboy clay leaves, and I strongly suspect that you have 
gotten into the Cretaceous." 
It is interesting to know that the fossil leaf impressions from 
these clays are probably all of new species, but the fact that they 
are new, as Professor Ward remarks, decreases their diagnostic value 
in determining the age of the deposits. The age of the pottery 
clays could not therefore, without more collecting at least, be decided 
o Ann. Rept. Geol. Survey Arkansas for 1892, vol. 2, pp. 20-21. 
