Diagenetic effect of firm ground over grainstone microstructure: A) Field photograph showing the basal part of the 2D outcrop with angular cross-bedded grainstone overlain by an interpreted firm ground; B) PPL photomicrograph of the cemented grainstone facies below firm ground; and C) PPL photomicrograph representing the less cemented grainstones of the angular cross-bedded grainstone showing further compacted textures during later burial.