138 Transactions of the Academy of Science of St. Lowis 
The relation of this area to the Ironton fault is not clear, 
but apparently the fault passes to the west of the shut-in. The 
alignment of the granitic intrusion and the pink rhyolite south 
of the shut-in suggests intrusion along a fault parallel to the 
Ironton fault. This fault would have to be of small displace- 
ment, however, as the black and red porphyry outcrops ‘on both 
sides of the rhyolite intrusion. There is a suggestion of struc- 
ture at right angles to the trend of the Ironton fault in the 
strike of the contact bétween the flow breccia and the black and 
red porphyry and in the northeastward bending of the intrusive 
rhyolite. Mapping in detail with a more accurate base would 
give a clearer idea of the relation between the strike of faults, 
contacts, and flow lines and might indicate whether the dips of 
the felsite were due to folding before faulting, drag along fault 
planes, or to intrusion, 
Belleview Valley has the appearance of a down-dropped 
block. Plate II shows this valley, as a square area of Paleo- 
zoic rocks surrounded by pre-Cambrian rocks, in the western 
part of the Iron Mountain quadrangle and the eastern part of 
the Edgehill quadrangle. It is bounded on the northeast by the 
Ironton fault with the straight escarpment along Buford Moun- 
tain which has already been mentioned. On the northwest, the 
boundary is marked by the straight side of Logan Mountain 
and by a small outcrop of granite at the eastern end of the 
mountain. The southeast side of this block is bounded by the 
felsite hills along the Black River road and by the course of 
the headwaters of the East Fork of the Black River. Dake (11) 
mentioned these three linear topographic features as suggest- 
ing pre-Cambrian faulting. The southwest boundary of this 
block is not marked by any escarpment which suggests that this 
was a hinge, the greatest movement on the block being on the 
Buford Mountain edge. However there has been some faulting 
along the southeast boundary for basic dikes lying along the 
boundary line show displacement. The eastern corner of the 
block contains the Graniteville granite mass which has appat- 
ently been intruded along the fault planes. 
