sandstone (i.e., sedimentary rock composed of grains 0.06–2 mm 【0.0024–0.08 inch】 in diameter) containing over 50 percent rock fragments. Lithic arenites most often are of gray or salt-and-pepper colour because of the inclusion of dark rock fragments, mainly slate, phyllite, or schist but also andesite or basalt. Lithic arenites formed by rapid deposition in areas subject to crustal deformation.