00317nam a2200133Ia 4500008004100000020001500041041000800056084001200064100002000076245003000096260003600126653000900162653001200171160808s1976    xx            000 0 eng d  a0408705736  aeng  aH192CC  aWebster, Robert  aGems /cby Robert Webster  aLondon :bButter Worths,c1976.  aGems  aGeology