| Rating | Solver | Clue |
|---|---|---|
| CAVE | Limestone formation | |
| OOLITE | Limestone formation | |
| STALAGMITE | Limestone formation | |
| STOCK | An irregular metalliferous mass filling a large cavity in a rock formation, as a stock of lead ore deposited in limestone. | |
| MUSCHELKALK | A kind of shell limestone, whose strata form the middle one of the three divisions of the Triassic formation in Germany. See Chart, under Geology. | |
| SUBCARBONIFEROUS | Of or pertaining to the lowest division of the Carboniferous formations underlying the proper coal measures. It was a marine formation characterized in general by beds of limestone. | |
| CLIFF LIMESTONE | A series of limestone strata found in Ohio and farther west, presenting bluffs along the rivers and valleys, formerly supposed to be of one for... | |