Fossil Tunnel, or World 2-A, is the alternate level of Rubble Ruins. It's theme is a bone cave with many Spine Coasters.
- Star Coin #1: In the first underground green warp pipe. The player must ride the Spine Coaster all the way to the end to grab it.
- Star Coin #2: Upon reaching the point where the player must switch Spine Coasters, jump onto the bottom coaster to get the Star Coin.
- Star Coin #3: Ride the last Spine Coaster all the way to the end, and the Star Coin is just up ahead.
- Dry Bones
- Super Dry Bones