BY A. GIBB MAITLAND, C.E., F.G.S. 2S 



In its geological structure, the region bordering the Gulf of 

 Mexico is identical with that of the Atlantic Border. The 

 formations exposed belong respectively to the Cretaceous, 

 Tertiary, and Eecent. The dip, which is practically the same 

 throughout, averages 20ft. per mile. There is a much 

 greater thickness of beds in the Cretaceous series here than in 

 the States on the Atlantic Border. The thickness nowhere 

 exceeds 2,600ft., and the width of the outcrop is not far from 

 50 miles in places. 



In the State of Alabama, the water-bearmg strata have 

 been studied in considerable detail, and accurately mapped. 

 The results have been published on the Geological Map of the 

 State, issued in 1894. The beds from which the bulk of the 

 water is derived are known by the name of the Eutaw and 

 Tuscaloosa beds, which represent the Potomac Group in the 

 States to the north-east. The strata consist of about 1,300ft. 

 of cross-bedded sands, sandy clays, and thin pebble beds. 

 These are estimated to cover an area of about 8,000 square 

 miles. 



The group enters the State on the eastern boundary, at the 

 town of Columbus, in the neighbourhood of which the width o^ 

 the outcrop is about 10 miles, and is crossed almost at right 

 angles by the Chattahoche Eiver. From the eastern boundary 

 of the State, the outcrop extends due west to the town of 

 Wetumpka, from which place its width gradually increases to 

 the north-western corner of Alabama. As measured along the 

 western frontier, from the base of the Lower Cretaceous to the 

 base of the impervious strata, the width is about 120 miles. 

 Nowhere does the surface occupied by these beds rise to a greater 

 altitude than 300ft. above sea level. (Plate I, fig. 1). 



The aggregate thickness of the formations exposed in what 

 may be called the Coastal Plain region has been found to be 

 about 5,500ft., of which 2,500ft. may be referred to the Cretaceous, 

 1,800ft. to the Eocene, and the rest to the later Tertiary and the 

 Quarternary. The whole of the beds dip at a low angle, about 

 40ft. per mile to the south, which carries them below the level 

 of the Gulf of Mexico. 



At the town of Livingston, Sumter County, at an altitude 

 of 150ft. above sea level, and situated just to the north of the 



