"Radioisotope dating is done on the rocks that fossils are found in ."
"Actually , the dating is done on layers above and below the rock in which fossils are found . You see , generally fossils are found in some sort of sedimentary rock . And sedimentary rock can not be dated . But a layer of volcanic ash above and below the fossil can be dated and thus give a date within a range ."
"Radioisotope dating is done on the rocks that fossils are found in ."
"Actually , the dating is done on layers above and below the rock in which fossils are found . You see , generally fossils are found in some sort of sedimentary rock"