170 GEOLOGIOAL SURVEY OF ALABAMA. 
JONES’ AND Rovup’s VALLEY. 
An inspection of the map will show that the long valley 
separating the Cahaba from the Warrior Coal Field, is much 
more complicated in its structure than the valley between 
the Coosa and Cahaba Fields. 
Like the Cahaba Valley, this has essentially an anticlinal 
structure, and like that valley, this structure is somewhat 
masked by faulting ; but in addition to this we can trace out 
in every part of this valley, two anticlinal folds separated 
by asynclinal. Almost everywhere in the valley the anti- 
clinal folds have been pushed over towards the northwest in 
accordance with the general law of Appalachian structure, 
and the axes of the folds are close to their northwestern 
edges. In the synclinal we find its axis near the south- 
eastern edge, as is the case in the upper part of the Cahaba 
Coal Field. 
There are two classes of exceptions to this general plan 
of structure noticed in Jones’ Valley. First, where the anti- 
clinal is nearly symmetrical, and the strata on the two sides 
of it dip in opposite directions at approximately the same 
angle. Oneinstance of this may beseen in the valley between 
McAshan Mountain and East Red Mountain, and another in 
the upper part of the valley west of Springville, in Clayton’s 
Cov@ and northeastward ; both of which will be more par- 
ticufgsy described in another place. In these cases also 
the crest of the anticlinal is. unbroken, while everywhere 
else thé @ests are marked by thrust faults. 
‘The@econd class of exception to the general plan of 
structure is seen in those cases where the strata dip towards 
the northwest, and the fault is found along the southeastern 
border of the arches, making what we have spoken of above 
as a reversed thrust fault. Two well marked instances of 
this class of exception occur in Jones’ Valley; one being 
west of McAshan Mountain, the other being in the north- 
eastern part of the region of the present map; but the most 
important instance is in Murphree’s Valley.a The case of 
a To Mr. A. A. Gibson belongs the credit of first calling attention to 
this type of structure in Alabama. In his report on Murphree’s Valley, 
now in manuscript and soon to be published, will be found full details 
of the typical locality. 
