THE MAD PROPERTY IS UNDERLAIN BY CRETACEOUS AGE SEDIMENTS OF THE JACKASS MOUNTAIN GROUP. THESE SEDIMENTS WHICH INCLUDE VOLCANIC ARENITE, SILT- STONE AND CONGLOMERATE, STRIKE NORTHEAST AND DIP 25 DEGREES WEST. ALTHOUGH FOLDING IS MINIMAL, FAULTING IS VERY STRONG PARTICULARLY AT 50, 105 AND 143 DEGREES. GOLD-SILVER MINERALIZATION OCCURS IN LESS THAN ONE METER QUARTZ-CARBONATE CONFORM- ABLE AND CROSS-CUTTING VEINS, AND IN MASSIVE SULPHIDE VEINS. THIS MINERALIZATION IS ACCOMPANIED BY HIGHLY ANOMALOUS AMOUNTS OF ARSENIC, MERCURY, AND ANTIMONY, AND IS BELIEVED TO HAVE ORIGINATED FROM PORPHYRITIC INTRUSIONS STRUCTURALLY CONTROL- LED ALONG THE MAJOR 105 DEGREE FAULTS.