A conglomerate or grit rock, consisting of rounded pebbles and sand firmly united together.

An impure sandstone consisting of rock fragments and grains of quartz and feldspar in a matrix of clay-size particles.

a quartz sandstone which includes noticeable amounts of mud and/or mica. Sometimes called a "dirty sandstone".

A sandstone containing quartz, feldspar, and rock fragments in a clay matrix.

a rock similar to sandstone but with a significant content of mud/silt; graywackes exhibits poor sorting and bedding, characteristic of minor water action

A dark gray, consolidated, coarse-grained sandstone consisting of poorly sorted angular to subangular grains of quartz, feldspar, and dark rock and mineral fragments embedded in a matrix of compact clay.

A dark-gray, coarse-grained, poorly-sorted sandstone.

Sandstone composed of poorly sorted angular clasts.

rock composed of angular grains of quartz, feldspars and various rocks enclosed in a weakly metamorphosed argillaceous matrix. Metagraywacke: metamorphosed graywacke.

a sedimentary rock, a coarse sandstone or fine conglomerate consisting of rounded fragments of rocks and minerals bound in a fine-grained matrix. [AHDOS