Often, if we are looking at the old legends correctly, not so much repressed as altered to accomodate various political systems and powers.
It is interesting, though, that as Christian missionaries have traveled the world, they have found that God has left a 'hook' of original material somewhere in each culture upon which the Gospel could be hung, which would help the people understand. A couple of books which give some good material concerning this are "Eternity in their Hearts" by Richardson and "Bruchko" by Bruce Olsen. I highly recommend both.
In terms of what Adam himself passed down, though, it must have been suppressed and/or changed rather quickly, for Noah is listed as a peacher of righteousness (2 Peter 2:5) who condemned his entire generation because of his faith! (Heb. 11:7). In other words, all except this one man and at least one of his sons (Shem), had fallen away from the truth by his time.