Related Clues:
- Small well in rock
- Hardly hard rock?
- Mammoth snagger
- Mammoth-preserving locale
- Rock hotel in auction
- Easily split layered rock
- Rock fracked for gas
- Fracking material
- Rock that's "fracked"
- Mud, after compaction
- La Brea hazard
- Sticky spot
- Something fracked in fracking
- *Sedimentary rock
- Source of gas market includes hydrogen