Bulletin, Issue 954

15 meters 30 meters 40 percent adit aluminous lateritic soil analyses Areponápuchic average Baja California black calcite bodies boehmite braunite breccia calcite Camagüey cavities centimeters chemical Chihuahua chromite composition containing Cretaceous crystals depth Distrito dumps Durango east explored fault feet Fissure deposit fractures Gavilán Geological Survey gibbsite grade granite Haiti Josefina kilometers lateritic soil layers limestone Lucifer manganese deposits manganese oxides Manuel Benavides material Mesa meters deep meters long meters thick meters wide Metric tons Mexico Minas mined minerals northwest occur Parral percent of manganese percent of silica pounds probably production psilomelane quartz region reserves rhombohedron rhyolite road Rochelois Plateau samples San Antonio San Luis Potosí scheelite schist serpentine shaft silica SiO2 Sonora southeast southwest stopes strike suboptical calcite surface trail tuff tungsten twinning lamellae usable calcite valley veinlets vertical Veta volcanic rocks width wolframite zone