Over 95% of the total coastal plain area lies at less than 100 meters altitude. Very rarely does its surface extend higher. Coastal plains are bounded at depth by "archs," "shelves" and "basins" developed on the surface of older rocks.
Answer: Stretching inland from the Gulf Coast, the Coastal Plains, encompassing about two-fifths of the state's land area, range from sea level to about 1,000 feet (300 metres) in elevation.
