In talking about the floor of the cave, where water is flowing in a stream-like fashion, it is a structure known as a rimstone dam. This is a structure that has a slight upturn, similar to an outer rim on a soup bowl. It is formed as a result of calcite deposition in areas where the water flow slows enough for the calcite to precipitate out of solution.
Other structures that are the product of calcite deposition are the stone icicles that descend from a cave's ceiling, called stalactites. These are formed as a result of calcite in water, dripping through cracks in the cave's ceiling. Over time, the calcite builds up layer by layer, and forms a stone icicle. These stone icicles can generate from the cave's floor as well. These are called stalagmites. Sometimes, the deposition will be sufficient enough to generate a stalactite formation from the ceiling and a stalagmite formation from the floor. When they join in the middle, this is called a column.