As the passageways were being formed, some would become too wide to support the ceiling, causing the ceiling to fall. Formed at or under water level, air bubbles surrounded by calcium carbonate solution solidify leaving behind round nodules. This acid is formed by rainwater picking up carbon dioxide from the air and from decaying plants and animals as it seeps through the dirt. Once this acid would reach the limestone under the soil, it would enter into the cracks and dissolve the limestone away to create the rooms, passageways and speleothems of the cave. Flowing or dripping water agitates particles within the pool, preventing particles from becoming cemented to the cave floor.
Cave pearls can be spherical, oval, irregularly shaped, or even shaped as cubes.
Silica nodules formed during the time that limestone layers were being laid down. Chert is not as easily dissolved away by carbonic acid as limestone. Due to this fact, nodules of chert are sometimes left behind on the cave wall after the formation of the cave has stopped. These can be seen in Manitou Dome. The name given to a formation where a stalactite and a stalagmite grow together.