Based on the results of drilling operations on Enewetak (Eniwetok) Atoll, in the nearby Ralik Chain of the Marshall Islands, Bikar may include as much as 4600 feet of reef material atop a basalt rock base. As most local coral growth stops at about 150 feet below the ocean surface, such a massive stony coral base suggests a gradual isostatic subsidence of the underlying extinct volcano, which itself rises 10,000 feet from the surrounding ocean floor. Shallow water fossils taken from just above Enewetak's basalt base are dated to about 55 mya.