Potters Clay. 303 I Obfervation. > \ It is very impure, being mixed with fand and gravel, and alfo iron ochre- It may be confidered as fandy potter’s clay, mixed wifli mica and iron •chre. SECOND SUBSPECIES. Potters Clay. Topferchon.—Werner. ' This fubfpecies is by Werner divided into two kinds, the a. Earthy, and b. Slaty. a. Earthy