Cryptic Chasm

In this dungeon after the 30th floor there is a fake exit that says the following within 6 different slates. There are unown stones that are on floors: 1, 5, 10, 15, 20, 25
 * 1) If this is where you ended then you took a false path
 * 2) Below the center of obscurity lies the key
 * 3) If you are unkown of origin then that is all you need to know
 * 4) By dawn you must swim the seas but by dusk you must walk on land
 * 5) An odd past awaits you
 * 6) Ahead lies a creature of unimaginable power

The Recruitable Pokemon are: The Mystery Eggs are:
 * Woobat 3% floor 15-40 night
 * Sigilyth -2% floor 30-40
 * Cacnea
 * Mawile
 * Sableye
 * Spoink
 * Gligar
 * Drifloon floor 30-40

Using Dig on the area where the poke is leads you to a room with 2 Enigmatic keys. Both keys are needed.