Subvar. h. Flaggy. Var. d. Slate. Subgroup C. Fault rock. i. Conglomeritic. k. Concretionary. n. Mudstone. o. Tutenic shale. Subvar. a. Roofing slate. b. Slab slate. c. Pencil slate. d. Novaculyte. f. Carbonaceous. g. Arenaceous. h. Tuffose. i. Ribaned. j. Conglomeritic. Group B.-ROCKS FOR THE MOST PART CHEMICALLY FORMED. I. Minerals occurring as rocks (see page 17). b. Pyrite. c. Cinnabar. d. Boracite. f. Aragonite. j. Opal. k. Fluorite. 1. Barite. s. Stibnite. t. Arsenopyrite. u. Sulphur. w. Chalcopyrite. |