MISSISSIPPIAN. 407 



and therefore antedates Hartselle by many years. Tuscumbia, being a geographical term, 

 will have to replace the much older Lithostrotion of Prof. Safford. 



The fossils from the Shenango appear to be those characteristic of the Chester of the Mis- 

 sissippi basin. Forms belonging to that epoch have been collected in Peimsylvania, Virginia, 

 Kentucky, and elsewhere. Fossils collected by Andrews in 1869 from the Maxville localities 

 in Ohio and by Stevenson in 1870 from the same limestone in West Virginia were submitted to 

 Mr. F. B. Meek, who pronounced them distinctly Chester. Prof. K. P. Whitfield afterward 

 figured and described the Ohio forms, referring them practically to the same horizon. Still 

 later, in 1901, Stevenson collected carefully at a locality in Fayette County of Pennsylvania 

 and submitted the specimens to Mr. Weller, who found that the fauna contains some St. Louis 

 as well as the Chester forms. There is, however, practically no change in the fauna from the 

 bottom to the top of this locality, the same forms, with two or three exceptions, being found 

 throughout. The Chester forms predominate, and of those belonging to the St. Louis some 

 lived on into the Chester at typical localities within the Mississippi basin. The same fauna 

 occiu-s in Randolph County of east-centrafWest Virginia and in Washington Coxmty of Virginia 

 at the Tennessee border. In Tennessee and Alabama the Maxville (Hartselle) is clearly Chester. 

 The Kentucky geologists of the Second Survey make the Maxville the upper part of their St. 

 Louis, but it overlies the Lithostrotion bed, the lower part of their St. Louis. No list is given 

 of the fossils which lead to classification of the limestone as St. Louis. 



The Tuscumbia is practically nonfossiliferous at most localities in Pennsylvania. In 

 Tennessee and Alabama, as well as in Kentucky, lAikostrotion canadensis is the characteristic 

 fossil, and it is associated with other forms belonging to the St. Louis. 



Girty •* comments on the correlation which Stevenson thus suggests as follows : 



In the correlations quoted from Stevenson there appears to be an error. Stevenson there 

 places the Shenango above the Maxville and the Tuscumbia, whereas on page 42 he assigns the 

 Shenango to the horizon of the Burlington and Keokuk and correlates it with the Logan which 

 underlies the Maxville in the Ohio section. It seems almost certain that in the former case 

 he is speaking of the Shenango shale of White and in the latter of the underlying Shenango 

 sandstone of the same author. There can hardly be a doubt that the Shenango sandstone is 

 the same in part at least as the "Logan group" of Ohio (now the Blackhand and Logan forma- 

 tions) . The correlation of the Shenango sandstone with the Blackhand and of the Logan with 

 the Shenango shale is suggested by the lithologic sequences. Professor Stevenson, however, 

 appears to consider the Shenango shale as occupying a much higher position. He places 

 it equivalent to the upper Mauch Chunk and above rather than below the Maxville. If this is 

 so, there must be an important interval between the Shenango shale and the Shenango sand- 

 stone representing the lower and middle Mauch Chunk, so that it would be inadvisable to 

 include the shale and sandstone under the same formation name. If Stevenson is right, the 

 sandstone alone should be called Shenango. 



Some doubt also is involved in the use of the name Tuscmnbia for the lowest of these 

 three formations, with which he aligns the Fort Payne of Tennessee. I have good faimas of 

 both the Fort Payne of Alabama and the overlying Hartselle of the same area and I also have 

 a collection from the limestone at Tuscimibia, Ala., which is without much question the Tus- 

 cumbia limestone. The Tuscumbia fauna is decidedly different from either the Fort Payne 

 or Hartselle faunas and much more closely allied to that of the overlying Bangor. 



J-K 15. IOWA, ILLINOIS, MISSOURI, ARKANSAS, AND OKLAHOMA. 



The region here comprised is that in which the Mississippian is typically devel- 

 oped as a great limestone, which is divided locally into several formations according 

 to the nature of the strata, and these are grouped according to their fossil contents. 



a Comment on manuscript. 



