292 CLAY GENUS. « Chemical Characters. .y ,, (*•' ' It is fufible into a white enamel without addition before the blow pipe. Constituent Parts, Silica 6 9>S Alumina 13.6 Sulphat of lime 12,0 Oxyd of copper °>7 ■ of iron °>3 According to Bindheim. Geognostic Situation, It forms one of the condiment parts of certain kinds of greenftone, occurs alfo in fyenite, and is ac companied with mica, fhorl, and feldom with iron pyrites. Geographic Situation, It was firft difcovered in the ifland of St Paul, on the coafl: of Labrador, where it is dill found in con- fiderable