Geological Survey of Alabama. 13 



Section at Nanafalia Landing. 



1. Green-sand marl, highly fossiliferous, the main form being Gryphcea 

 thirsce, with a few other shells, such as Turritella Mortoni, a Flabellum, 

 etc. This is the lowermost of the Gryphsea beds, and is here about 20 

 feet thick. 



2. Dark-blue, almost black, laminated clay, devoid of fossils, but 

 passing below gradually into a bluish marl 3 to 4 ft. 



3. Bluish, green-sand marl, containing a few shells in the upper three 

 or four feet, but becoming much more fossiliferous below. This bed 

 contains a great variety of beautifully preserved and easily detached 

 fossils, which can, however, be seen only at a low stage of water. 

 Thickness 8 to 10ft. 



5. The Naheola and Matthews' Landing Section. It is difficult to give 

 the thickness of the strata of this section, since it varies on the two rivers. 

 We have placed it at 130 to 150 feet. The strata are gray, sandy clays 

 in the main, alternating with cross-bedded sands. The beds of dark, 

 sandy clay containing the marine shells lie at the base of the section ; but 

 the Naheola bed on the Tombigbee, while occupying a similar strati- 

 graphical position to the Matthews' Landing bed on the Alabama, differs 

 from it in the character of the materials as well as in the fossils. The 

 two have not been seen so near together as to enable us to determine their 

 relative position. 



The following details are given of the 



Section at Matthews' Landing. 



1. Bluish-black, micaceous, clayey sand, with finely preserved fossils. 

 Very dark when wet, but becoming grayish blue on drying. Crumbles 

 upon exposed slopes, liberating the fossils, which lie in the crumbs thus 

 produced. This is capped by an indurated, sandy, concretionary ledge. 

 Thickness of the fossiliferous strata about 5 or 6 ft. 



2. Gray sands with slightly yellowish cast, showing a tendency to in. 

 durate into lens-shaped bowlders one to two feet thick and three to four 

 feet wide. These sands are also fossiliferous, but much less so than the 

 preceding beds ; the fossils are difficult to get out because of the hardness 

 of the material : 3 to 4 ft. 



3. Bluish, micaceous, clayey sand, much like No. 1, but not holding 

 all of its characteristic fossils. Where this stratum lies exposed to the 

 sun and weather upon flat or nearly horizontal benches, it disintegrates, 

 like No. 1, into crumbs, in which the liberated fossils lie loosely ; but 



