...schist is generally not distinct; the two are commonly separated by a transitional zone which varies in thickness from a fraction of an inch to several feet. The topaz rock retains either a faint banding (see pi. 8, B) or the pattern of a breccia (see pi. 8, (3),...

...area the veins — called "siliceous reefs" — strike east to northeast, are of steep dip, and vary in thickness from a fraction of an inch to several feet. The country rock is granodiorite containing, in order of abundance, plagioclase (Anw to AnM), quartz, orinecíase,...

...dirtygray sandstone containing thin calcareous beds and numerous lenses and layers of sandy shale ranging in thickness from a fraction of an inch to several feet. The distribution of the oil in the sand is probably dependent to a considerable degree on differences in...

...foot (ll.5 m) beds of conglomerate and sandstone with interbeds of shale and siltstone which range in thickness from a fraction of an inch to several feet. The thick-bedded conglomerate and sandstone are well cemented by quartz, chalcedony, and iron oxide, and...