TOPOGRAPHY AND GEOLOGY. 19 
Tertiary is widespread in the eastern and southern parts of the^State, 
it is at many places overlain by a thin coating of Quaternary deposits, 
so that the true character of the Tertiary beds is more or less obscured. 
The lignites exposed along Saline and Ouachita rivers, the marls 
exposed at White Bluff and Red Bluff on Arkansas River, and the 
shell marl on Little Crow Creek, St. Francis County, are all Tertiary. 
The hard sandstones in Crowleys Ridge about Gainesville are of the 
same age/' 
QUATERNARY SYSTEM. 
A thin sheet of sedimentary materials, consisting of sands, clays, 
and gravels, cover the Tertiary area of the State and some of the 
adjacent Paleozoic rocks. The country lying north of Arkansas 
River and east of the Paleozoic hills belongs to the Quaternary. The 
lowest strata exposed in Crowleys Ridge belong to the Eocene. All 
the river bottoms are of recent origin, while the loess capping Crowleys 
Ridge and likewise the river terraces and second bottoms of all the 
important streams belong to the Pleistocene. The waterworn mate- 
rials that cover the foothills of Lawrence, Independence, Pulaski, 
Saline, Hot Springs, Clark, Pike, Howard, and Sevier counties are of 
late Tertiary or Pleistocene age. 
a Call, R. E., The geology of Crowleys Ridge: Ann. Rept. Geol. Survey Arkansas for 1889, vol. 2, 1891. 
