Dramatic changes in sea level occurred throughout the cenozoic era and the rise and fall of sea level is recorded in the rocks of the amazing numbers of fossil clams, snails, and sand dollars can be found in these marine rocks, along with fossilized whale bones and shark teeth.

Ans. 'Coastal plains of Virginia.'

The Cenozoic era is a geological era that last about 65 million years from the ending of Cretaceous period. During the end of Cretaceous period and early Cenozoic era, drastic sea-level changes are recorded in the rocks of coastal plains of Virginia, due to their tectonic stability and rapid sedimentation.

The regions near coastal plains of Virginia include diverse fossil types, such as fossils of trees, mollusks, and vertebrates (whales).  

Thus, the correct answer to be filled in the blank is 'coastal plains of Virginia.'

then that particular organisms become extinct.

this transfer is call conjunction