The Petty Dwarves: History
The Petty-dwarves were Dwarves of several houses, who had been exiled for reasons unknown in very ancient times during the Peace of Arda. They were the first to cross the Blue Mountains in the First Age, and established strongholds in Beleriand before the building of Nogrod and Belegost in the Blue Mountains, and before the Elves arrived. They delved the very ancient settlements of Nulukkizdin (Nargothrond) and Amon Rûdh but they dwindled before the Ñoldor returned to Middle-earth.