Find the Beast's Lair

Journal
''Timothy the Enchanter warned me of a fell beast in the Spectral Mines that "once crawled among us" and chews on the bones of its enemies. He's worried it's returned and wants me to help confirm or refute this theory. I'm to find the lair in the Spectral Mines, gather three distinctly different bones from the lair, and return the bones to him.''
 * The Sacred Oracle Orb of Obliteration and Book of Mighty Weapons are given to you when you first receive this quest.