VALLEY REGION DETAILS ; SHADES VALLEY. 171 
McAshan Mountain will be considered further on, but we 
may conveniently now describe the occurrence in township 
15, range 1, east, along the northeastern border of the 
valley. Here, not far from the line of the A. G.S. RB. R., 
there is a fault along which on the northwestern side the 
strata of the Knox Dolomite with moderate northwesterly 
dip, are in contact with the strata of the Sub-Carboniferous 
of the Cahaba Field on the southeast, with nearly vertical 
position or with very high southeasterly dip. 
This is the reverse of the usual order of things, and may 
be explained as already shown upon the supposition that 
the fold, instead of having had its crest pushed over towards 
the northwest, has had the trough shoved under from the 
southeast side. At the lower end of this fold in the north- 
west corner of township 16, range 1, east, its anticlinal 
character is more apparent. Beyond this fold to the north- 
west, we see a synclinal with Sub-Carboniferous chert and 
Oxmoor shales, as the uppermost beds, and this is followed 
in the same direction by a simple anticlinal and then by 
the synclinal of Blount Mountain (Coal Measures), north- 
east part of township 15, range 1, west, and beyond that the 
-anticlinal of Murphree’s Valley not shown in the limits of 
this map. Southwest from the end of this Blount Mountain 
synclinal of the Coal Measures we see the underlyige beds 
gradually coming to the surface in the order, Subgarboni- 
ferous, Devonian, Red Mountain, Trenton, and Knox Dolo- 
mite. The upper formations involved in this synctinal from 
the Sub-Carboniferous to the Trenton, do not hepn’ many 
miles below the end of the Blount Mountain, but the syncli- 
nal of the Knox Dolomite may be followed down nearly to 
Bessemer. It makes all that ridgy land between Chalkville 
and Hagood’s Cross Roads, the flint ridge of the North 
Highlands about Birmingham, and its continuation down to 
the old Smith place near Bessemer. Indeed, with certain 
modifications it may be followed almost the entire length of 
this map. ; 
From Trussville down to the lower end of Jefferson 
county, in the southeast part of township 20, range 5, west, 
the feature that perhaps most strikes the eye is the wide 
valley based on the upper rocks of the Sub-Carboniferous, 
