Intriguingly , carbon dating reveals that many of the fossils of the larger creatures , especially the dodos and tortoises , accumulated between about 4235 years and 4100 years ago , the researchers report in the march issue ofnaturwissenschaften .
Along with small fossils such as pollen , seeds , insects , and snails , the team 's recent diggings have brought to light a rich layer of fossils of bats , songbirds , dodos , and extinct giant tortoises .
