PCA 25-ft Stand of the Sea on Oahu, Hawaii
An ancient calcareous beach deposit is exposed in several quarries on Oahu, Hawaii, 25 ft (7.5 m) above mean sea level and is overlain by a reef of the 95-ft (29-m) stand of the sea of Yarmouth interglacial age. A solution unconformity separates the two deposits, indicating that the sea fell lower than 25 ft after the beach rock was deposited.