134 Transactions of the Academy of Science of St. Louis 
the Graniteville area indicating the granite was intruded after 
the formation of the iron deposits. On Cedar Hill, iron ore 
has been mined from two veins which dip 20°, in the direction 
S. 45° W. which is similar to the dip in the pyroclastics at 
Pilot Knob (10). The ore is laminated and has a brecciated 
zone for a footwall suggesting that the ore solutions may have 
followed a thin bed of pyroclastics. Pilot Knob contains thicker 
pyroclastics with larger iron deposits. Crane (10) mentions a 
zone of shearing between the upper and lower ore beds at Pilot 
Knob, which consists of soft, grayish, micaceous material hav- 
ing a Maximum thickness of three feet. The shearing zone may 
be due to a minor fault following a bedding plane in the pyro- 
clastics. There are three vertical veins of iron ore striking 
northeast on Shephard Mountain to the west of the fault line, 
which are apparently in joints or faults, as they cut across the 
strike of the felsite. Iron ore occurs in nearly vertical veins 
east of Ironton on Shut-in Mountain but the felsite is also ver- 
tical so that the veins may follow bedding planes. 
At the shut-in on Stouts Creek, east of Ironton, there is an 
excellent exposure of igneous rocks. Because of its accessibil- 
ity and because of the variety of rocks exposed, this locality 
was chosen for detailed study. Plate VI shows the areal ge- 
ology of this region. The rock exposed along Highway 70 
through the shut-in and along Lake Kilarney is a black porphyry 
with red phenocrysts giving it a granitic appearance which sug- 
gests that it may be an intrusive but the abundant flow lines are 
more characteristic of an extrusive. At the shut-in the flow lines 
are vertical and strike N. 10° E., while a half mile north along 
the road the dip is 80° to the northwest, and the strike is N. 50° 
E. A half mile beyond this point the dip becomes 65° to the 
northwest and the strike N. 80° E. 
On the top of the hill to the north of Highway 70, 4 
purple flow breccia occurs and a small area of this same rock 
crosses Highway 70 and Stouts Creek at the east end of the 
shut-in. This isolated patch of breccia may indicate a depres- 
sion on the top of the black and red porphyry into which the 
breccia flowed or it may be due to local folding or faulting. If 
