Gulf Coast of the United States Pensacola, St. Petersburg, Tampa, and increasingly, Sarasota. All are the centers of their respective metropolitan areas and contain large ports. (Baton Rouge is relatively far from the Gulf of Mexico; its port is on the Mississippi River, as is the port of New Orleans.) The Gulf Coast is made of many inlets, bays, and lagoons. The coast is also intersected by numerous rivers, the largest of which is the Mississippi River. Much of the land along the Gulf Coast is, or was, marshland. Ringing the Gulf Coast is the Gulf Coastal Plain which reaches from Southern Texas to the western
Gulf of Mexico zone of uniformly thinned transitional crust, which is half the typical 40 kilometer thickness of normal continental crust. It was at this time that rifting first created a connection to the Pacific Ocean across central Mexico and later eastward to the Atlantic Ocean. This flooded the opening basin to create the Gulf of Mexico as an enclosed marginal sea. While the Gulf of Mexico was a restricted basin, the subsiding transitional crust was blanketed by the widespread deposition of Louann Salt and associated anhydrite evaporites. During the Late Jurassic, continued rifting widened the Gulf of Mexico and progressed to the