Assertion: mastodon | /r/AtLocation | the fossil record
Facets:
Source sentences:
text: Mastodons first appeared in the fossil record of what is now Northern Africa in the Oligocene of the Paleogene period about 30 million years ago, while Primelephas, the ancestor of mammoths and modern elephants, appeared in the late Miocene epoch, about seven million years ago.
text: Mastodons were only distantly related to modern elephants and first appeared in the fossil record about 30 million years ago.