From introduction: Travertine is defined for this paper as a carbonate-mineral deposit dominated by calcium carbonate, formed through the agency of spring water. Thus is includes terms such as tufa, onyx marble, calcareous sinter, and calcareous spring deposits. However, we exclude carbonate deposits in caves, those formed by wave action and other shore processes, and bioherms except as algae may participate in the process of calcium carbonate from spring water