1) Shale 
Mudstone, a type of mudrock, is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm (0.0025 in) with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the appearance of fissility or paral...
sedimentary rock composed primarily of clay- or silt-sized particles (less than 0.063 mm [0.0025 inch] in diameter); it is not laminated or easily ... [3 related articles]
A detrital sedimentary rock composed of clay-sized particles.
A sedimentary rock composed of clay-size particles but lacking the stratified structure that is char
Fine grained sedimentary rock composed of lithified silt and clay particles.
A fine grained sedimentary rock similar to shale but more massive.A fine-grained sedimentary rock similar to shale but more massive.
Fine-grained sedimentary rock made up of clay- to silt-sized particles (up to 0.0625 mm/0.0025 in)
A fine-grained detrital sedimentary rock made up of clay- and silt-sized particles.
Muds and silts that have been compressed to form a hard, fine-grained rock.
a relatively soft rock formed largely of fine clay. Compressed, flaky mudstone is often called shale.
a clayey rock with the texture and composition of shale but little or no lamination.