Note 2883 — BOOK XVII. THE NATURAL HISTORY OF THE CULTIVATED TREES.

Probably meaning “smooth marl;” a variety, Fée thinks, of argillaceous marl, and, perhaps, the potter’s argillaceous marl, or potter’s argil. He suggests, also that it may have possibly been the Marga fullonum saponacea lamellosa of Valerius; in other words, fullers’ earth.