Department of the Gulf north. On November 3, 1863, the northern boundary was extended to latitude 33° north. On July 25, 1863, the department/district was transferred to the Department of Mississippi and Eastern Louisiana. It remained in that department only until January 28, 1864, when it was transferred to the Department of Alabama and Eastern Mississippi. Upon being transferred, the department/district boundaries were redefined as beginning at the mouth of the Pearl River, running north to latitude 32° north, east to the Georgia State line and south to the Gulf of Mexico. On May 8, 1864, the boundary was again modified to define the
Gulf of Mexico basin Gulf of Mexico basin The formation of the Gulf of Mexico, an oceanic rift basin located between North America and the Yucatan Block, was preceded by the breakup of the Supercontinent Pangaea in the Late-Triassic, weakening the lithosphere. Rifting between the North and South American plates continued in the Early-Jurassic, approximately 160 million years ago, and formation of the Gulf of Mexico, including subsidence due to crustal thinning, was complete by 140 Ma. Stratigraphy of the basin, which can be split into several regions, includes sediments deposited from the Jurassic through the Holocene, currently totaling a thickness between 15 and