GEOLOGY OF GILES COUNTY, VIRGINIA 
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passing just north of Kimballton. It seems to be a single fault 
east of New River but westward it is generally in two steps. In 
this paper, this fault will be called the Wolf Creek fault. Near 
the Narrows, Giles and Romney rocks are brought by this dis- 
placement in contact with the Shenandoah limestone. 
The Saltville fault parallels the southern boundary of the 
county. It runs through Poplar Hill, Staffordsville, and a little 
south of the crests of Buckeye and Spruce Run mountains. Every- 
where on the southerly side of the fault is the Shenandoah lime- 
stone, but on the north, there are Ordovician, Silurian and even 
Devonian rocks in various places. It seems to be a two-step fault 
in Buckeye Mountain. 
All of the above mentioned faults are of the thrust type, and 
in each case the older rocks were thrust over younger ones from 
the southeast. The dips, then, on the southerly side are regularly 
south-south-east ward, rarely more than 25° in the case of the 
Saltville fault, and seldom exceeding 35° in the other two previ- 
ously mentioned breaks. Other faults of Giles County are of 
the normal type, and are too small to be named, being ordinarily 
confined to a single member of one formation, with displacements 
of less than fifteen feet. 
Walker Mountain is formed by the upturned edges of the 
Clinch and Bays formations to the south of the Saltville fault. 
Buckeye and Spruce Run mountains are formed by the up- 
turned and south dipping Rockwood, Clinch and Bays on the 
north side of Saltville fault. The crests are on the south limb of 
an anticline whose axis lies just north of them. In their south 
slopes these mountains still preserve enough structure to show 
that they are the remnants of a syncline which was broken by the 
fault. Thus the strata on the south side of the fault were thrust 
up many hundreds of feet so that Shenandoah lies against Rock- 
wood and Clinch. This displacement carried the south limb of 
the syncline and the succeeding anticline (whose axis was be- 
tween Buckeye and Walker mountains) so high that they were 
all eroded in the pre-peneplain periods of erosion (probably early 
Mesozoic time). Walker Mountain, then, is the southern limb 
of the anticline with the strata dipping away to the south. 
Pearis and Angels Rest mountains are opposite sides of a 
synclinal structure pitching off to the west by southwest, so that 
Mill Creek is flowing in an erosion widened, structural valley. 
