Pg. 284, 286-292. Ardian series (Ardian epoch). Analysis of physical characters and paleontological features of Pennsylvanian rocks in North America leads to conclusion that stratigraphic cleavage at two positions within system has paramount significance. Three series recognized: Ardian -Lower Pennsylvanian, Oklan -Middle Pennsylvanian, and Kawvian -Upper Pennsylvanian. Ardian series includes Springerian and Morrowan rocks which are classed as stages. Thickness of sediments about 5,000 feet in type area where both Springerian and Morrowan stages are present. MILLERELLA is only genus of fusulinids in Ardian, and Ardian may be designated as zone of MILLERELLA. Rocks of Ardian age probably widespread in Appalachian region; seemingly most rocks referred to lower Pottsville are of Ardian age. Time equivalent is Ardian epoch.
Type sequence: Ardmore basin south of Arbuckle Mountains, southern OK. Named from first syllable of Ardmore.

Source: US geologic names lexicon (USGS Bull. 1200, p. 129).