248 ASHLEY — GEOLOGY OF AKKANSAS. [May 13, 



uplift is a remnant of a westward extension of the Appalachian 

 chain. As this view presents certain difficulties, there has also been 

 advanced the theory that that westward extension, if it existed, was 

 to the south, possibly crossing the northern part of Louisiana. In 

 such a case these beds may have been continuous with, though 

 varying from, the Carboniferous exposures on the west of the Ap- 

 palachians. 



To the west the same beds run into the Indian Territory, and the 

 Carboniferous is found as far west as the looth meridian and in 

 Texas as far south as the thirty-first parallel. 



To the north the strata are thought to have been originally con- 

 tinuous with the strata just north of the Ouachita uplift. 



Several attempts to prove this continuity were made, but without 

 much success, though nothing to the contrary was found. 



Direction and Conditions of Depositions, 



Mr. Griswold, from his study of the novaculite area, came to the 

 conclusion that the sediments with which he had to deal came from 

 the south. ^ This was largely based upon the fact that the sand- 

 stones overlying the novaculite on the south are largely represented 

 on the north by shales. Apparently the same fact is also to be ob- 

 served in our area. This is shown by the difference in the topog- 

 raphy : almost no shale being met with in the southern part 

 of the region, and east and west valleys of any breadth are un- 

 common, while as the novaculite mountains are approached there 

 are broad valleys with frequent exposures of shale. It was at first 

 thought that this might be due to the strata as a whole having a 

 slight south dip, so that the shales, which are low in the series, were 

 not as fully exposed, but, as will be shown later, the proof is to the 

 contrary. There also appears to be more shale exposed over the 

 eastern part than over the western ; but this is not marked enough 

 to make one feel sure but that greater erosion may have had some- 

 thing to do with the difference. 



V. General View of Structure After Folding. 



In Fig. I is given a generalized section across the State in a 

 north-south line through range 30 W. 



"^Geol. Survey of Ark. ^ Rep, for 1890, Vol. iii, p. 193. 



