Boston Meeting of the Geological Society, 147 
plain, facetted pebbles may be frequently found at depths of several feet 
below the surface, and in practically all cases the facetted side of the 
pebble lies upward. From this it is argued that the shaping of the 
pebbles was effected after they were brought to their present positions; 
and hence it is further argued that during the growth of the gravel 
plain it must have been a subaerial delta, built by streams heading in 
the ice sheet among the hills of the terminal moraine, the "backbone" 
of the Cape. As in ordinary deltas, a portion of the deposit must have 
been laid down beneath the water-level; but another portion must have 
been built above water-level ; and the facetted pebble beds of the Cape 
seem to belong to the latter. Until the division between these two por- 
tions of the stratified sands and gravels is identified, the postglacial 
changes of level in Cape Cod cannot be determined. 
In the discussion following this paper, Mr. G. K. Gilbert referred to 
a locality about fifteen miles east of WatertowD, in northern New 
York, where the carving of pebbles by the natural sandblast has ap- 
parently been accomplished since a recent clearing of the surface. Prof. 
Shaler objected to the assumption that the facetted pebbles were 
carved by wind-blown sand; he thought it more likely that they were 
shaped by splitting on joints that had been opened during some retreat 
of the ice; after which a new advance carried the pebbles forward 
again. Prof. Davis replied that, while such weathering might naturally 
happen, he could not appeal to it to explain the forms of firm-textured 
pebbles, waterworn on one side, sharply facetted on the other, lying 
with facets uppermost in undisturbed stratified deposits, several miles 
from the moraine in which the sands and gravels were derived. 
22. Paleozoic intra formational conglomerates. Charees D. Wal- 
oott, Washington, D. C. (Read by title.) An intra-formational con- 
glomerate is one formed of material derived from and deposited within 
a formation. The paper described conglomerates of this type occurring 
at various Paleozoic horizons in the St. Lawrence valley and along the 
Appalachians from Canada to Alabama. 
23. Paleozoic overlaps in Montgomery and Pulaski counties, Virginia. 
M. R. Campbeel, Washington, D. C. (Published by permission of the 
Director of the U. S. Geol. Survey.) The region along the Norfolk & 
Western railroad, between Christiansburg and Max Meadows, Virginia, 
is an area of very complicated geology. The prevailing ideas are that 
it is traversed by numerous faults, many of which are transverse to the 
general lines of structure; and they have been so described by Rogers, 
Lesley, Fontaine, Stevenson, and McCreath and d'lnvilliers. 
During the present season the writer worked this region quite care- 
fully, and came to the conclusion that all of these supposed cross faults 
are in reality lines of unconformable deposition between Devonian and 
Carboniferous sediments and the Cambro-Silurian or Shenandoah lime- 
stone. Price mountain is the best known of these areas and consists of 
an isolated anticline of Lower Carboniferous coal-bearing rocks, entirely 
surrounded by the Shenadoah limestone. Everywhere around the 
mountain the red shale at the top of the Carboniferous rocks is in con- 
tact with the limestone and appears to be but slightly disturbed: dips 
vary from 15° to 30° away from the axis in all directions, while the 
structure of the limestones, so far as could be seen, is extremely compli- 
cated and shows no agreement with the upper beds. 
No theory of faulting could place the mass in its present attitude ;ind 
relation to the limestone, and the writer was forced to the conclusion 
that it was unconformably deposited in a basin produced by folding of 
the limestone and was later upraised and folded into an anticline. The 
same evidence was found in Ingles mountain, where the Devonian black 
shales rest on the limestone ; and in the region north of Pulaski the 
same phenomenon is seen, and again from Max Meadows to Clark's 
Summit. 
