ogygian

from The Century Dictionary.

• Of or pertaining to Ogyges, a legendary monarch in Greece (Attica, or Bœotia, etc.), of whom nothing is known; hence, of great and obscure antiquity.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of or pertaining to Ogyges, a mythical king of ancient Attica, or to a great deluge in Attica in his days; hence, primeval; of obscure antiquity.