Investigations into the future development of the Stonyfell and Greenhill quarries have involved detailed geological mapping and the study of future market trends. Geological factors have been shown to affect the quality of stone present within the quarries. The market trends clearly indicate a decreasing demand for some of the individual products. A new development scheme has been proposed, involving physically linking the two quarries, thus allowing full use to be made of a valuable resource within easy reach of the metropolitan market. A continued supply of aggregates until the year 2000 would then be assured. Recommendations also include the permanent rehabilitation of the eastern faces of Stonyfell Quarry.