VALLEY REGION DETAILS ; SHADES VALLEY. 179 
It may be that the structure here is similar to that of the 
valley abeut Birmingham. In a cut on the Birmingham 
Mineral Railroad, just beyond the Edwards ore banks, the 
Cambrian limestone and shales have been laid bare, and ex- 
hibit one of the most perfect examples of the contortions 
and foldings into which it is possible to throw solid rocks. 
The limestones have been pressed together into a number 
of close folds, as perfectly and completely as one could do it 
with a bundle of sheetsof paper. The edges of these folded’ 
limestone layers are seen in zig-zag lines all along on both 
sides of a cut of forty or fifty feet in length. These layers 
of limestone are quite pure and have been used in making 
lime which slakes very well, showing that it is of very good 
quality. Now, while at the base of the cut and for ten feet 
or so above the level of the track, the limestone is quite 
fresh, and unweathered, it passes very suddenly into a yel- 
lowish stratified clay in which may be followed perfectly all 
the lines of folding of the limestone itself, as if the upper 
part of the limestone, near the outcrop, and where long sub- 
jected to the action of the atmospheric agencies, had been 
converted into the clayey matter. If the limestone were im- 
pure and charged with clayey material, we might suppose 
that the calcareous matter was leached out and the alumi- 
nous part left, but the limestone is pure enough to afford 
good, thoroughly slaking lime, so that the whole appearance 
is as though the limestone had been removed by leaching 
agencies, and its place taken by a sandy clay. We should 
in any case expect to find a gradual transition from the one 
kind of material to the other, but as I have said, the change 
is rather abrupt. 
The strata of the Red Mountain may be followed with 
some interruption from opposite Woodstock down to Vance’s. 
on the west side of the valley. 
The fault which occurs on this side of the valley appears. 
to run in and out approximately parallel to the edge of the 
Coal Field, now leaving a pretty full series of strata between 
it and the Coal Field, now lapping up almost upon the beds 
of the latter, by pinching out or engulfing the intermediate 
formations. 
West of Vance’s we see a narrow anticlinal fold which 
