Bone Dragon

Breeding
The can be bred by selecting a Fire Dragon or fire hybrid dragon to mate with an Earth Dragon or earth hybrid dragon at the Breeding Cave/Epic Breeding Island.

Breeding a Fire Dragon with an Earth Dragon can also result in a Lava Dragon.  EXPIRED 

Earning Rates
Coin per minute: Level 1: 7 / Level 10: 43

Dragon Earning Rates without boosts.

Boost Calculation Guide to use with the page linked above.