JlLY 3. 1003.] 



SCIENCE. 



23 



and Ocnla formations, and the upper are the 

 Chattahoochee and Chipola. 



Since no mention is made in these sections 

 of any Grand Gulf, we may safely assume 

 that none exists there between the Vieksburg 

 and the Chattahoochee, and yet on the up- 

 lands, on botli sides of the Chattahoochee River 

 the characteristic Grand Gulf beds may be 

 seen occupying the surface witli the usiial 

 capping of Lafayette sands. 



Mr. Gilbert Harris also publishes a good ac- 

 count of this river section in his ' Bulletin 

 No. 15 of American Paleontology.' 



In this article, as well as in that of Messrs. 

 Dall and Brown, it is demonstrated beyond all 

 question that the Chipola overlies the Chatta- 

 hoochee, apparently conformably and certainly 

 without the intercalation between them of any 

 Grand Gulf beds; and in the same way the 

 Chipola is conformably overlain by the Alum 

 Bluff beds, and these in turn by the Chesa- 

 peake marl, followed by what Professor Dall 

 calls an aluminous clay, which he considers 

 as belonging probably also to the Chesapeake. 

 " It will be seen on examination " (of the 

 sections and diagrams) " that, while the series 

 is not complete in any single section, taken 

 collectively there is no gap outstanding be- 

 tween the beds and, humanly speaking, no 

 room for misapprehension as to their position 

 and age."* 



Let us now trace up the Grand Gulf beds 

 along these rivers. Nobody will deny that 

 they overlie the Vieksburg limestone, both in 

 Alabama and in Georgia, clear up to the 

 Chattahoochee River where the post-Vicksburg 

 series of marine Tertiary beds begins. 



Mr. Harrisf gives a section of the bluff at 

 the old Chattahoochee Landing, in which, 

 underneath the orange and red sands, pre- 

 sumably Lafayette, at the top of the section, 

 there are some twenty feet of purplish clayey 

 sands, and light sands and clays, which he 

 says ' resemble Grand Gulf.' No doubt they 

 are Grand Gulf, and here they overlie the 

 Tertiary beds consisting, according to Pro- 

 fessor Ball's determinations, of Chattahoochee 

 and Chipola. 



* DrII and Brown, loc. cit., p. 162. 

 t IjOc. cit., p. 52. 



Near the top of every section of Professors 

 Dall and Brown there is shown a bed, their 

 No. 2, which lias been referred by them to 

 the Lafayette, but which, from the descrip- 

 tions, appears to include both the Lafayette 

 and the Grand Gulf. For the authors em- 

 phasize the facts that these beds are uearly 

 seventy feet thick, and that they are often 

 different in composition, structure and color 

 from the more homogeneous (Lafayette) for- 

 mation to the northward. 



It is safe to say then that in this Appalachi- 

 eola and Chattahoochee section, from the 

 Vieksburg limestone up to the top of the 

 Chesapeake Miocene as shown at Alum Bluff, 

 none of the beds which take part in the forma- 

 tion of the river bluffs has ever been consid- 

 ered Grand Gulf, unless it be those capping 

 the bluffs, above all the Tertiaries, and cov- 

 ered only by the Lafayette and more recent 

 deposits. 



2. Conecuh River, Escambia County, Ala. — 

 In the upper part of township 2, range 12, in 

 this county, the bank of Conecuh* River is 

 formed by the Vieksburg limestone, while in 

 the lower part of the same township, some 

 four miles distant, the baiik is formed by gray 

 sandy clays holding Miocene fossils. At both 

 localities the Grand Gulf beds, sands, clays 

 and lignites, overlie the Tertiary formations, 

 and form the surface of the country interven- 

 ing, with the usual capping of Lafayette. 



3. Chichn.sawhay River, in Greene County, 

 Miss. — About five miles above the confluence 

 of Leaf and Chickasawhay Rivers on the latter 

 stream, we have recently examined a bluff at 

 the base of which is a shell marl, with innu- 

 merable shells of Rangia Johnsoni, and a few 

 other forms characteristic of the Pascagoula 

 horizon. Above this and forming the upper 

 half of the bluff are tyijical Grand Gulf 

 strata, sands and clays with lignite bed and 

 silicified trunks of trees all in direct contact 

 with the Pascagoula marl. 



4. MoJ/ile County Artesian Borings. — These 

 borings have been made at and near Mobile 

 and at Alabama Port. The deepest is the 



* By inadvertence this was called Escambia 

 River in our previous note. 



