L. C. JOHNSON— THE CHATTAHOOCHEE EMBAYMENT. 129 



Flint river; the next rocks seen are at the <>1<1 Chattahoochee landing, on the road 

 to the village, and it is upon these that Mr. Langdon founded the Chattahoochee 



formation. The northern and eastern extension, in exactly this form, has not yet 

 been determined. Southward it lias a very considerable inclination, so that in- 

 stead of covering high hills, as about Chattahoochee, it sinks to the place of the 

 lower rocks at Aspalaga landing and goes out of sight at Rock bluff. 



Fossils are not common in this basal portion, and their place is usually filled with 

 calcite ; and the rock is of considerable weight and density. At Aspalaga, however, 

 a layer near the top is tilled with casts and impressions of gasteropoda and coral.-, 

 including conspicuously the large Orbitulites floridana. 



This phase of the formation constitutes the upper or country rock of Gadsden 

 county. It is largely exposed on Little river and its branches. It is of interest as 

 the bed rock upon which lie the phosphates of this county, notably at Aspalaga, 

 where the top of this layer is 40 feet above the water; above lie as much more of 

 brown and dark-colored clays or altered marls, with thin layers of shells; all very 

 much decomposed except an Ostrea and a large pecten (Pert, n madisonius) resem- 

 bling that of Waldo, on the eastern side of the peninsula. For the sake of distinc- 

 tion, we may call this upper bed the Aspalaga* phase of the Waldo formation. 



The following section displays the relation of the beds at Aspalaga (on Apalachi- 

 cola river, in section 35, township 3 north, range 7 west) : 



Feet. 



1 . Pine level with much gravel in poor sand jTO 



2. Sands of number 1 washed off in places expose a very hard red clay alter- 



nating in places with ferruginous sandstone, forming cliffs ; some also pure 

 enough for limonite 20 



:!. Stratified sands and sandy clays, water bearing, having springs at the base 



and in intercalated clay beds % 50 



4. Tough calcareous clays, including the residuum after lime of the shells is 



leached away, generally dark colored % 60 



5. Limestone forming bluffs for over two miles, unevenly scored by erosion ; 



rising higher toward north, subsiding toward south; passes beneath the 

 river at Kock bluff, though very high at Chattahoochee || 40 



At bock bluff, live miles south of Aspalaga, the heavy rocks of the Chattal - 



chee lie below the water line. The clays of number 4 of the preceding section 

 are lien- much reduced, while the stratum itself increases in thickness and carries 

 more of 1 he calcareous sand, with numerous well preserved pectens and other shells. 



* Tin ■ old site of Aspalaga village and posl office is in section 35, township :'• north, range 7 west. 



Rock bluff i- on I hattahoochee river, 5 mil ss south of Lspalaga, Chattal :hee being iboul the 



same distance norl hward. 



t Elevations ind thicknesses ascertained by aneroid. 



J 2 and 3 may be assigned to the Lafayette formation. 



g Exposure no! clear enough to ->•■• subdivisions, bul in gullies some dec lyed shells are found, 

 well .-I- Pecten and Ostrea which resemble forms found at Waldo; al one spol in a trough of num- 

 ber 5 a phosphate bed occurs. This member may be called the Aspalaga clays. 



[n the lower layers the fossils are obscured by infiltration of calcite; the upper layers are full 



i>i fossils, corals, and lamellibranch, and Orbi ulites lloridana. \\ M it Pleasant thi- upper layer 



i~ found o\ er i" < feel ■*■••% e the ri 



XVII Bum '■! "> Soi . Am., \ oi , 3, 1891. 



