This site preserves an oxbow along the Athabasca River north of Fort McMurray and includes the largest tufa deposits in the region. Tufa deposits formed here because the bedrock under much of the area consists of oil-bearing sandstones with underlying limestone formations. Water from springs flows underground through the limestone and bubbles to the surface where sandstone and limestone meet. Spring water flows through the formations dissolving some of the limestone and combining with carbon dioxide in the water to form bicarbonate. When the flow surfaces at La Saline, carbon dioxide is lost to the atmosphere, leaving behind calcium carbonate. Calcium carbonate does not dissolve in water; instead, it precipitates out forming the hard, crust-like deposit known as tufa (or travertine). The tufa at La Saline has formed an extensive cone that is three metres in diameter. Saline Lake is one of the most important waterfowl lakes in the area.