604 A. W. GRABAU TYPES OF SEDIMENTARY OVERLAP 



distance from its source, partly by winds and afterward by currents, 

 when it had fallen on the surface of the sea which then covered this 

 region."* Small concretions of iron pyrites occur in the shale. 



The shale is here overlain by from 150 to 225 feet of the Fort Payne 

 chert. This begins usually with heavy beds of chert at the base, with only 

 a little limestone or shale, passing upward gradually into purer limestone 

 and "without abrupt transition into the Bangor limestone above." This 

 series is from 700 to 800 feet thick. The Fort Payne chert is very 

 fossiliferous, and is the "siliceous group" of S afford, which he divided 

 into a lower, or Protean (Lauderdale, McCalley), and upper, or Litho- 

 strotion (Tuscumbia, McCalley). Ulrich makes the Tullahoma of 

 central Tennessee and the Fort Payne of eastern Tennessee equivalent, 

 and correlates both with the Kinderhook and Osage of the Mississippi 

 valley. There is here an inconsistency, for the upper part of the Fort 

 Payne (Tuscumbia) is clearly of lower Saint Louis age, as shown by the 

 abundance of Lithostrotion canadense (=L. mamillare) . 



Stevenson considers that the upper part of the Fort Payne is unques- 

 tionably Tuscumbia, but he also says:f 



"It is difficult to determine, by means of available observations, whether or 

 not the Fort Payne of the extreme southeasterly areas embraces any Tuscum- 

 bia. For the most part the features are those of the Lauderdale (Logan), 

 there being an almost total absence of limestone in the upper part; but in 

 Calhoun county of Alabama, very near the extreme southeast exposure, one 

 finds the Tuscumbia clearly present One may conjecture that as the Lauder- 

 dale is practically without limestone nearer the shore line the Tuscumbia 

 would undergo the same change, so that the thin Fort Payne on the border 

 would represent both. This is in accordance with the conditions in this 

 region, as each of the Mississippian formations apparently overlaps its prede- 

 cessor." 



Nor is the Protean, or Lauderdale, the equivalent of the whole Tul- 

 lahoma (as denned by Ulrich — that is, = Kinderhook-Osage) ; for, ac- 

 cording to SaffordiJ 



"This lower, or Protean, member of the Siliceous group, is, in general, 

 equivalent to the divisions of the Lower Carboniferous limestone lying below 

 the Saint Louis limestone. It is, perhaps, more especially the equivalent of the 

 Keokuk limestone; it contains, however, some Burlington forms." 



He lists the following species from this member : § 



Spirifer imbrex Hall. "Occurs immediately above the Black shale below 

 Huggins's mill, near Manchester, in Coffee county, associated with Productus 



* Hayes : McMinnville folio. 



t J. J. Stevenson : Lower Carboniferous of the Appalachian basin. Bull. Geol. Sox;. 

 Am., vol. 14, 1903, pp. 14-96. 



JSafford: Loc. cit., p. 342. 

 r^glbid. : Loc. cit, pp. 342, 343. 



