The Swan Hills Member is divisible into a lower Dark Brown submember (stromatoporoid reef platform) and an upper Light Brown submember (stromatoporoid biohermal reef complex). Twenty-two rock types and eight environmental facies, distinguished within the reef complex, indicate an atoll-like reef development. Geomorphic features including outer slope, reef rim, reef crest, and central lagoon are evident. Biocalcarenite and biocalcirudite with well-developed porosity are present in the reef-rim positions, whereas micritic rock types with low porosity are present in the central part of the reef complex. Large stromatoporoids, brachiopods, and crinoids are present in forereef positions; organic reef and backreef accumulations consist of Stachyodes and large stromatoporoids; and lagoonal parts are dominated by Amphipora with a few occurrences of ostracods, Foraminifera, and calcispheres.