A feldspathized sandstone containing 8.6 per cent of K 2 O, largely in the form of authigenic orthoclase, is a distinctive lithic unit in the lower part of the Upper Cambrian Franconia formation. The rock is composed of feldspar, 48 per cent; quartz, 44 per cent; glauconite, 5 per cent; muscovite, 2 per cent; collophane, 0.5 per cent; leucoxene, 0.4 per cent; and traces of zircon, tourmaline, and garnet. The chemical and physical properties of the rock are discussed.

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