* A simple gross sand [[Subsurface maps#Isopach|isopach]] map that is essentially unaltered by results of considerable additional drilling. Such correct predictions represent work that has earned a high scientific confidence level and therefore is well past step 3. | * A simple gross sand [[Subsurface maps#Isopach|isopach]] map that is essentially unaltered by results of considerable additional drilling. Such correct predictions represent work that has earned a high scientific confidence level and therefore is well past step 3. |