The many islands and cays stand on banks, in shallow water, with oceanic depths among and between them.

The region has, doubtless, been subjected to alternate periods of uplift and depres- sion in past geologic time, but the vertical movements have prob- ably been relatively small ; during times of uplift, some of the present islands may have been connected, but there is no evidence that there ever was land connection with either Florida, Cuba or Hispaniola.

Most of the islands are low, but hilly and rocky, the ranges of hills usually running lengthwise of the island ; on New Providence, the hills rise to about 100 feet elevation; on Cat Island, aneroid barometer readings indicated altitudes up to 205 feet (published records of greater elevations on Cat Island were not substantiated by our observations) ; on Watlings Island, hills rise to about 140 feet.

Most of Andros, the Great Bahama and Abaco are low and nearly level.

At points where the hills come to the sea there are bold rocky headlands, such as Columbus Bluff, at the southern end of Cat Island.