Kevin DeYoung has asked a similar question to mine about the historical Adam. Essentially his point is that in the genealogies of 1 Chronicles there is no indication from the author that part of the record is mythological or figurative while the rest is historical. You can check it out here.
Just another side note on this issue: after my first post on this a friend questioned whether or not the biblical narrative can be more than history. His question was, in other words, whether the biblical text does more than just relate historical events. My answer was of course yes – the Scriptures are the inspired interpretation of the historical events of God and his people. But that does not make them a- or un-historical. We can recognize both the historical veracity of the biblical record and the inspired interpretation that the Scriptures provide of those events. So when I say “there is no indication from the author that part of the record is mythological or figurative while the rest is historical,” I am not in any way intending to separate the biblical authors’ ability to both relate historical events accurately and interpret history in theologically meaningful ways, but am actually trying to argue that these two things are not separable in Scripture. One can recognize the Bible’s historical accuracy and its ability (or, even stronger, its intention) to interpret history at the same time.