568 A. F. FOERSTE 



The red phase of the Dixon bed' has not been seen anywhere 

 east of a line connecting Martin's mill and Rise mill. The upper 

 part of the Silurian section at W. D. Helton, 3^ miles west of 

 Waynesboro, probably belongs to this horizon, but it does not 

 have a red color, nor is it a conspicuously clayey section. The 

 horizQn of the Dixon bed must be represented by some of the 

 rocks exposed along the headwaters of Buffalo River, west 

 of Riverside; but, if so, they do not possess the strong, brick- 

 red coloring shown by the Dixon bed farther westward. 



The exposure at Montgomery's mill is too low to include the 

 Dixon horizon. 



At the bridge, i J^ miles west of Pegram, the base of the 

 Brownsport bed is represented by a layer of clay, 8 feet thick, 

 including thin fragments of limestone. This clay contains the 

 typical Brownsport fauna. Beneath it is a section of clayey 

 limestone, white or bluish in color, which evidently must weather 

 readily into a sort of clay, since it is exposed only along the 

 railroad cut. The thickness of this clayey limestone cannot be 

 determined definitely, owing to the irregular dip, but it is known 

 to exceed 22 feet and may equal 40 feet. It is considered the 

 equivalent of the Dixon bed. Northeast of the railroad cut, up 

 Furbee and Greer Hollow, well-bedded limestone flags represent 

 the top of the Lego bed. The Lego bed is at least 28 feet 

 thick, a mile and a half east of Pegram, in the bluffs southeast of 

 the home of Sam Walker. Its total thickness is unknown. 



It is evident that the red color is characteristic of the Dixon 

 bed only in the Tennessee River sections. Even in the Tennes- 

 see River basin the red color is due chiefly to weathering, the 

 less weathered sections exposed by the more rapid cutting of 

 streams consisting more frequently of beds of red rock alter- 

 nating with layers of whitish limestone. It some sections the 

 whitish limestone equals, or even slightly exceeds, the red clayey 

 rock in quantity. Where weathered, the whitish limestone is 

 tinged more or less strongly with red. 



There is usually no sharp line of demarkation between the 

 Lego limestone and the Dixon red clay. A series of transition 

 beds almost always connects the more typical parts of the sec- 



