Three sandstones of early middle Ordovician (Buffalo River) age are prominently developed and widely distributed in the Ozark region of northern Arkansas. They are, name from oldest to youngest, Kings River, Calico Rock, and St. Peter sandstones. The Kings River sandstone is the basal member of the Everton formation over a large area in the western and central Ozark region except at places where it is underlain by the Sneeds limestone member of the Everton. The Calico Rock sandstone is conspicuously developed in the central part of the region and lies stratigraphically below the middle of the Everton formation. The St. Peter sandstone overlies the Everton unconformably and is the most widely distributed of the three sandstones extending from northwestern Arkansas to the Mississippi Valley alluvial plain.

*Includes: 187 pages, 15 plates, 22 figures and 57 tables

Bulletin 4 (8.78 MB)

Plate 1 (180 KB)

Plate 1 Supplement (1.79 MB)

Plate 1A (151 KB)