Well washed Trilobite/echinoderm biosparite with pelleted glauconite grains and quart from Central Texas. Typical of Cambrian platform (epieric) seas. with grains of glauconite, with trilobite and echinoid fragments. There is a mix of well sorted grains that are both rounded and angular. The matrix is a combination of poorly washed sparite and locally micrite, so portions of this sediment could be considered to be a packstone. Local crinoidial fragments have developed overgrowths.
Glauconite grains are the green pellets, possibly faecal, composed of this iron-rich clay. Glauconite is an indicator of shallow-water, nearshore, marine sedimentation associated with maximum flooding surfaces.