Everyone including Chirp carefully climbed down the cliffs to the river to have a look around. Down below the dam was a remarkable gorge and rock formations. One large boulder in particular was perforated like Swiss cheese.
Vugs! that is what looks like the Swiss Cheese. It happens when Limestone is turned into Dolostone.
Limestone is calcium carbonate (Ca2CO3) and Dolostone is calcium magnesium carbonate (CaMgCO3).
Without getting too much chemistry involved, the carbonate (CO3-) molecule would much rather partner up with the magnesium than the calcium. So as water rushes by the limestone, the calcium is replaced with magnesium, with in turn makes the molecule smaller, and creates the vugs (swiss cheese)
Absolutely great thread, my brother and I are heading next year to the North Maine Woods for a week, your thread has been great inspiration.