What are the difference between reworked fossils and leaked fossils?

From the law of faunal succession,older beds are characterized by fossils of older age and the younger beds are characterized by younger age fossils.But in some exceptional condition the younger fossils are reported in the older formation and those are termed as leaked fossils.

whereas,Fossils of older age occur in younger rock are known as reworked fossils.They are derived from the older rocks by reworking ad recycling of sediments.