Wiktionary
n. (context geology English) A compact stratum of partially permeable material rich in clay
Wikipedia
In geology, a claypan is a dense, compact, slowly permeable layer in the subsoil having a much higher clay content than the overlying material, from which it is separated by a sharply defined boundary. Claypans are usually hard when dry, and plastic and sticky when wet. They limit or slow the downward movement of water through the soil.
Usage examples of "claypan".
She proved to be a happy, reliable worker, and often accompanied her parents back to the claypan where they had made their camp.
One evening when Willabi returned home from south of the claypan near Lake Nubbera, she mentioned her suspicions to him.
The family remained at Bunda-Bunda, a claypan south of Jigalong, except for the occasional trips to the depot to pick up food rations and to gather the latest news and gossip.