CLASSIFICATION— GRADATIONAL AND LITHOLOGIC CRITERIA 475 



eolian agencies may have been more important in the transportation 

 uf their constituent materials than water. 



The late Devonian and Waverlyan elastics spread far inland in south- 

 eastern America from their Appalachian sources. There are no limestones 

 worth mentioning in the upper Devonian of New York, Pennsylvania, and 

 Ohio, nor in the Waverlyan, east of Illinois and north of east Tennessee. 

 The lower half to two-thirds of the succeeding Tennessean, however, is 

 made up, in the Appalachian Valley as in the Mississippi Valley, of 

 nearly pure limestone. Evidently a long time intervened, during which 

 the land which previously supplied the Devonian and Waverlyan elastics 

 in this middle Appalachian region was reduced to a condition of approxi- 

 mate baselevel. The only region in this country in which rocks ap- 

 parently of early to middle Tonnessean are are not limestone, or at least 

 highly calcareous sliale, is in northern Arkansas (Moorelield sliale and 

 possibly Batesville sandstone). Considerable bodies of limestone, in part 

 at least of Tennessean age, occur in the far west. 



THE LATE TENNESSEAN-EARTjY PENNSYLVANIAN PERIOD OF DIASTROPHJC 



ACTIVITY 



This quiescent stage was followed by the introductory phases of the 

 third grand diastrophic period or revolution. These began early in the 

 Chester series of the Tennessean — that is, with the Cypress sandstone in 

 the Mississippi Valley and the Batesville sandstone, the lower part of 

 which is probably somewhat older, in northern Arkansas. 



Both these sandstones derived their material wholly (the C3^press) or 

 in part (the Batesville) from the Ozark uplift, which had been just 

 sufficiently emerged in the preceding Meramec epoch, to neither receive 

 deposit nor to contribute more than insignificant amounts of clastic ma- 

 terial to the St. Louis and Spergen limestones which lie on its eastern 

 flank. However, during the deposition of these limestones, the surface 

 of the low land, which was largely covered by the cherty limestones of 

 the Osage, was being deeply decomposed and thus being prepared to supply 

 the fine sands of the Cypress and part of the Batesville^* when the 

 Chester elevation began. While the Devonian and early Kinderhook 

 sands derived from Ozarkia are readily identifiable as reworked St. 

 Peter sandstone, those of Chester age in no wise suggest the characteristic 

 rounded quartz grains of that formation. On the contrary, especially 

 those on the east side, look like the finely assorted wash of a deeply de- 



I 



54 A large part of the material of the Batesville, like that of the preceding Moorefield 

 shale of the same region, was probably taken from older sandstone and shale formations 

 to the south and southwest (Ouachita region), which at this time were slightly folded 

 and emerged and subjected to erosion. 



