‘This is the book of the history of Adam.'
This would fit most suitably as a colophon towards what has gone before, a record connected with Adam. But it could signify the history of Adam which was to follow.
This colophon (see article, " ") could well have been at the bottom of the tablet indicating what the tablet was about. Notice the specific reference in this case to the fact that it refers to ‘a book' (written record).