GEOLOGY OF CHILHOWEE MOUNTAIN, IN TENNESSEE. 77 
varies from that but little along the eastern side of the val¬ 
ley. The Cambrian limestone in the valley near Chilhowee 
is made up of two beds, each about 400 feet thick, and parted 
by 200 feet of green shale. They diminish rapidly south- 
westward, and at the southwest end of Chilhowee mountain 
they are only 200 feet thick in all. 
The cove limestone is 1,500 feet thick in each of the two 
deepest basins, and has in addition the closely associated 
red shale 1,500 feet thick. In view of the fact, to be discussed 
later, that the limestone rests on an uneven surface of erosion, 
it is quite possible that we do not have the full thickness 
anywhere exposed, but only the surplus over the height of 
the older surface. The deposit here may also be but the 
latter part of the equivalent formation in the valley, the 
earlier part being laid down at sea while this region was 
subaerial. On the score of thickness, therefore, the Cove lime¬ 
stone is more nearly equivalent to the Knox than to the Cam¬ 
brian limestone. If the red shales are included with the Cove 
limestone, it fairly equals the Knox. 
(b) In lithologic character there are no great differences 
between the Knox, Cambrian, and Cove limestone, because 
all the beds to be compared are limestones. The Cove 
limestone resembles both Knox dolomite and the Cam¬ 
brian limestone, in that all are massive. The Cove lime¬ 
stone also contains many beds of silicious dolomite, such as 
give its name to the Knox dolomite, and these are entirely 
wanting in the Cambrian limestone. Both Cove limestone 
and Knox dolomite contain large blocks and nodules of 
black chert, which are extremely rare in the Cambrian lime¬ 
stone. In fact, the only cherty horizon beside the Knox is 
the Carboniferous limestone on the west side of the valley. 
In both the Cove limestone and Knox occur layers of lime¬ 
stone conglomerate. These are the result of special condi¬ 
tions of erosion during the deposition of the dolomite, and 
the same special result in the Cove limestone is of great 
significance in indicating equivalence. 
(c) The red sandy shales associated wdth the limestone in 
