sentences:  Normally the rock lacks coherence and weathers into sand down to 6 m and even unweathered rock can be crushed to sand easily.However, near faults, ghost crystals of baryte make the sandstone harder and resistant.The lower sandstone (Upper Mottled Sandstone) has a full thickness of 305 m generally a reddy brown colour with some white patches, which give it its name, these patches are often associated with organic nuclei.