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caused by subsidence. Outcrops of sandstone are oriented <br /> in the terrain so that movement in either plane or in any <br /> direction within the plane could be detected visually. It <br /> was observed in several places that overhanging sandstone <br /> protected underlying shale so that the effects of weather- <br /> ing could be distinguished from subsidence effects . <br /> The area examined extended from the easternmost completely <br /> mined out area (which has been subject to subsidence forces <br /> the greatest length of time) closest to the surface, upward <br /> and westward across the central portion of the mined out <br /> area - - where maximum subsidence could be anticipated. <br /> Summary: <br /> The following observations of the inspection exhibited com- <br /> pletely negative response attributable to subsidence : <br /> 1. No vertical displacement is apparent at the <br /> shale contact beneath sandstone beds. <br /> 2. No horizontal or vertical movement is apparent <br /> in bedding planes or upon joints and fractures <br /> in sandstone outcrops. Most sandstones are not <br /> indurated adequately, nor of sufficient thickness, <br /> to resist moderately strong subsidence forces. <br /> 3. No vertical openings are apparent in shale out- <br /> crops. <br /> -5- <br />