94 J. J. STEVENSON — LOWER CARBONIFEROUS, APPALACHIAN BASIN 



in by far the greater part of this area. It is very calcareous, but it con- 

 tains few beds pure enough for lime, the most of it being calcareous shale 

 or argillaceous limestone, with varying beds of sandstone. The greatest 

 mass of comparatively pure limestone appears to be in the Cumberland 

 Plateau region of Tennessee, approximatel}^ on the line of the Pennsyl- 

 vania Alleghenies. 



The outlying areas in Virginia, Tennessee, Georgia, and Alabama show 

 the influence of near-shore conditions. The Virginia areas, within the 

 Great valley, have no limestones, only shales and sandstones being pres- 

 ent; whether or not any portion of these represent the Maxville could 

 not be determined. The Maxville is certainly present in the Chilhowie 

 mountains of east Tennessee, in the most easterly exposures within 

 Georgia, as well as in those of Alabama to the last exposure at the south ; 

 but in all of these it is no longer an impure limestone with sandstones 

 and shales, but a mass of shales and sandstones, the former often carbo- 

 naceous, with occasional thin beds of limestones ; and this mass attains 

 great thickness where it overlaps the Tuscumbia. Even on the western 

 side in Alabama the same condition exists, for there the sandstones and 

 shales predominate in the Hartselle. It is possible that some of the 

 overlying Bangor limestone belongs to the Maxville. 



The conditions during the Maxville differed in son:ie respects from 

 those during the Tuscumbia. The area of sedimentation was more con- 

 tracted on the northern and western sides, for no deposits were made in 

 northwestern West Virginia. It is altogether probable that in the early 

 ])art of the period much of central Pennsylvania received no deposit, for 

 there and in adjoining part of West Virginia one often finds a breccia 

 above the silicious limestone, consisting chiefly of fragments of that rock- 

 But while so much of the area was above water at the beginning and so 

 remained throughout the period, there was a subsidence in southeastern 

 Ohio, gradually extending northward, forming a bay reaching into Mus- 

 kingum county, so that along the outcrop from Muskingum southward 

 one finds lower beds appearing until the Tuscumbia is shown before the 

 Kentucky line has been reached, and in like manner, under cover, before 

 the West Virginia line has been reached. Under cover in West Virginia 

 the oil records show great irregularities within the counties bordering 

 on the shore area — sometimes apparently only the upper beds, at others 

 only the lower beds are present — and one is led once more to suggest 

 local crumplings and disturbances as the onl}^ explanation. 



At the east one finds evidence of continued lowering of the main- 

 land and of continued advance of the sea upon a low shoreline. The 

 deposits at the north were of fine material even to the Allegheny line, 

 with very little calcareous matter ; and this continued all the way to 



