The sediment in 129 is almost entirely micrite with a few indistinct bioclasis visi-ble. Texturally it is Ihus a mudstone, but is besl callcd a carbonate mudstone or linie mudstone to distinguish it from a terrigenous clastic mudstone.
129 Carbonate mudstone in plane-polarized light. Locality: Upper Jurassic, Morocco (x 20).
137