Cave of the Mounds the Interior and the National Park Service. To be considered a NNL, "a site must be one of the best examples of a natural region's characteristic biotic or geologic features." Cave of the Mounds is home to many varieties of speleothems. As with most caves, stalactites and stalagmites are common. Formations found inside the cave include: These formations come in many different brilliant colors such as reds, browns, blues, and grays. The reds and browns are caused by the presence of iron oxide in the formation. Similarly, blues and grays are caused by manganese oxide. Some speleothems are even partially
Calcium citrate sulfuric acid. In many individuals, bioavailability of calcium citrate is found to be equal to that of the cheaper calcium carbonate. However, alterations to the digestive tract may change how calcium is digested and absorbed. Unlike calcium carbonate, which is basic and neutralizes stomach acid, calcium citrate has no effect on stomach acid. Calcium carbonate is harder to digest than calcium citrate, and calcium carbonate carries a risk of "acid rebound" (the stomach overcompensates by producing more acid), so individuals who are sensitive to antacids or who have difficulty producing adequate stomach acid may choose calcium citrate over calcium carbonate