LITHARENITE

sandstone (i.e., sedimentary rock composed of grains 0.062 mm [0.00240.08 inch] in diameter) containing over 25 percent rock fragments. Litharenites 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. Litharenites formed by rapid deposition in areas subject to crustal deformation.