The identification of strata by the fossils they contained , pioneered by PERSON@1 , PERSON@2 , Jean d'Omalius d'Halloy , and PERSON@3 in the early 19th century , enabled geologists to divide LOCATION@1 history more precisely .

The identification of strata by the fossils they contained , pioneered by PERSON@1 , PERSON@2 , Jean d'Omalius d'Halloy and PERSON@3 in the early 19th century , enabled geologists to divide LOCATION@1 history more precisely .
