274 E. A. Smith — Remarks on a paper of 0. Meyer. 



6. The most positive and irrefutable evidence of the rela- 

 tive position of the White limestone and the Claiborne ferrugi- 

 nous sands is to be seen at the St. Stephens Bluff. There can 

 I imagine be no reasonable doubt that this bluff is made up of 

 the White limestone. In its upper part this limestone is in 

 places a mass of Orbiloides Mantelli, and in the lower part of the 

 bluff about 15 feet above the water level is a hard projecting 

 ledge, a foot thick, beneath which is a layer consisting of the 

 shells of Spondylus dumosus. 



A short distance — about half a mile — above the St. Stephens 

 landing, this bluff is interrupted by a ravine, on the other side 

 of which it may be seen again with identical characters ; Orbi- 

 toides limestone forming the upper part as at the landing below. 

 At the base of this part of the bluff occurs a red ferruginous 

 sand full of fossils — among which are Melongena alveata, Ore- 

 pidula lirata, Infundibulum trochiformis, Corbula Murchisoni, 

 Turritella lineata, Oytherea cequorea, Oliva Alabamensis, Turbi- 

 nolia Maclurei, Voluta Defranckii, Aslarte sulcata, and a number 

 of other forms which are found at Claiborne. Just over this 

 bed occurs the Scutella bed above referred to, and over that, 

 in direct contact, the white clayey limestone passing upward 

 into the Orbitoidal limestone. This ought to set the matter at 

 rest forever, so far as the relative positions of the Claiborne 

 sands and the White limestone are concerned. I shall not here 

 attempt to show that the White limestone of Alabama is the 

 representative of the Jackson and Vicksburg strata of Missis- 

 sippi ; but I can assert from personal observations that the 

 lower part of the White limestone of Alabama with its Zeu- 

 glodon bones and its limy soils corresponds with what Hilgard 

 marks as Jackson on his map, and that the upper part of our 

 White limestone is what Hilgard marks as Yicksburg. In p. 

 227 of Hilgard's Geology of Mississippi it is stated that the 

 Orbitoides limestone is directly overlaid by the sandstone of 

 the Grand Gulf group. This it seems to me is evidence that 

 the Orbitoides limestone (which Hilgard considers "Vicksburg) 

 is at the top of the series with which we are concerned. 



In paragraph 222, p. 144 of Hilgard's work, there is a dis- 

 tinct statement that the Yicksburg strata overlie those of the 

 Jackson. The same thing is shown in his diagram No. 32. 



b. From geographical position. 

 The Tertiary formations of Alabama have a southerly dip 

 (S. or S.W.) which will average some 25 to 30 feet to the mile. 

 This dip has been ascertained by L. C. Johnson and myself at 

 several places, and that it is very nearly the average may be 

 seen from the correspondence between our river sections and 

 the records of a boring made at Bladon Springs. These data 

 are very soon to be published. 



