Drill-prospecting by the Tennessee Valley Authority in 1941 near Clarksburg, Carroll County, Tennessee, disclosed a kaolin zone and associated series of sediments which are correlated with the Ackerman formation, the lowermost member of the Wilcox group (Eocene) of Mississippi. This formation, heretofore, has been considered to be absent on the outcrop in Tennessee, although the senior author had previously suggested its probable occurrence on the basis of stratigraphic and lithologic evidence.Certain features of the kaolin-bearing zone in the Clarksburg area are suggestive of deposition within a basin-like depression, and all evidence--both outcrop and drilling--indicates a sedimentary origin for the kaolin and associated sediments. The original source of the kaolin is believed to be the Porters Creek clay. It is suggested that, in the long Midway-Wilcox interval, the old Midway surface was deeply leached and ultimately developed a more or less continuous mantle of residual kaolin. In early Ackerman time, regional uplift and rejuvenation of erosive forces is believed to have swept these kaolins from the old Midway surface and deposited them in lagoons bordering the Ackerman sea.The drill-prospecting indicated 4,749,000 tons of minable clay which had a weighted Al 2 O 3 content of 34.3 per cent and a weighted Fe 2 O 3 content of 1.1 per cent.