264 RECORD OF DEEP-WELL DRILLING FOR 1905. 
Cretaceous — Continued. Feet.. 
Hard rock (no sample) 600-605 
Soft sandy marl (fine, olive-gray, slightly limy sand) 605-650 
Tough dark marl (no sample) 650-830 
Soft sandy marl (no sample) . 830-850 
Hard rock (no sample) 850-855 
Sand and shell (coarse gray sand, limestone, and bits of fossil shells) 855-870 
Dark and light sand (medium-fine gray, slightly limy sand, containing 
glauconite). 870-890 
Light-gray sand (coarser than preceding, containing glauconite) 890-918 
Rig used, rotary. Casing used, 140 feet of 4-inch; 340 feet of 3-inch; 870 feet of 2-inch. 
Length of strainer, 20 feet. Principal water bed from 870 to 918 feet. Elevation of well 
mouth, about 50 feet above sea level. Static head of water, +9 feet. 
1426. Well at Fort Moultrie, Charleston County. 
[Well completed in 1905. Authority, Capt. F. W. Cole, constructing quartermaster. No samples. 
Geologic correlations by W. B. Clark.] 
This is one of the very deep wells to obtain good water from sedimentary formations 
underlying the Atlantic Coastal Plain. It is thought that the water-bearing sands 
developed belong to the Potomac formation (early Cretaceous) and that the great mass 
of "marl," sand, and sandstone above 1,820 feet is of late (marine) Cretaceous age. Beds 
of Tertiary age ma} 7 occur down to a depth of over 500 feet. The samples saved were 
mostly mud which stuck to the drill, and the drillers' use of terms is probably not accurate. 
Exact identification of horizons and the grouping of strata are impossible, owing to the 
present imperfect knowledge regarding the deep-lying formations of the South Carolina 
coast. The log is given because of the depth of the well and the supply of water obtained, 
and also because it shows the general character of the beds overlying the water-bearing 
formations. 
Record of well at Fort Moultrie. 
Recent: Feet. 
Sea sand 0- 7 
Tertiary (?): 
Clay and marl 7 - 91 
Marl with layers of cemented shells 1 to 8 feet thick 91 - 348 
Hard sandstone 348 - 355 
Marl with shells 355 - 371 
Soft sandstone 371 - 374 
Marl with layers of hard sandstone . 374 - 417 
Hard sandstone with thin layers of marl 417 - 437 | 
Marl 437 - 515 
Cemented shell with thin layers of sandstone 515 - 523 
Tertiary and Cretaceous ( ?) : 
Marl with thin layers of sandstone 525 - 65C 
Marl with layers of shell to 720 feet 650 - 78( 
Sandstone 780 - 79( 
Marl with thin layers of sandstone 790 - 81( 
Sandstone with layers of marl 2 to 3 feet thick c. . 810 - 90( 
Marl and shells with thin layers of sandstone 900 - 95. 
Sandstone with hard layers 955 -1 , OCX 
Soft sandstone 1, 000 -1, 03« 
Soft, loose sand with layers of Inarl 1 , 030 -1 , 17 1 
Hard sandstone with layers of marl 1 , 170 -1,19 
Marl with hard layers of sandstone 1 , 190 -1 , 21 
Marl with thin layers of sandstone 1, 216 -1, 30 
