8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Range in the south center of the Roberts Mountains (1°) Quadrangle, Nev. The 
rocks of the interval are well exposed in parts of the Antelope, Monitor, and 
Toquima Ranges shown on the same sheet. The brachiopod fauna taken from 
rocks deposited during this stage is characterized by numerous orthids, the early 
strophomenids, plectambonitids, and the decline of the Syntrophiacea. Correla- 
tive rocks appear in the Arbuckle Mountains of Oklahoma and the Table Head 
series of Newfoundland. Exotic blocks containing fossils related to the Table 
Head of Newfoundland have been found in the boulders of the Mystic con- 
glomerate and from a little-known formation near North Cambridge, N. Y. 
Equivalents of these beds in Europe are not clearly understood, but some related 
forms have been taken in Norway and Estonia. 
Marmor stage-—The name for this stage is taken from the point called Mar- 
mor, just northeast of Friendsville on the Concord (T.V.A. 138-SW) Quad- 
rangle, Tenn. The reference section is along the railroad to the east of Marmor 
and extends to the adjacent Louisville (T.V.A. 138-SE) Quadrangle. This stage 
includes the Chazy group of rocks and its correlatives. 
Ashby stage-—The name for this stage is taken from a road intersection on 
Hogskin Creek, in the northeast quarter of the center subquad. of the Maynard- 
ville (30’) Quadrangle, Tenn. In the Hogskin Valley the formations Elway and 
Lincolnshire comprise this stage and are well exposed. In fact part of the Lin- 
colnshire and its shaly Hogskin member are especially well displayed. Kay 
(1948, p. 1402) places the formations of this stage in his Chazyan, but I believe 
that this is not justified on paleontological grounds. The Elway-Lincolnshire 
contains many Chazy elements, but it also contains brachiopods, such as the 
coarse-ribbed dinorthids, which are unknown in the Valcour or any other part 
of the Chazy group. It is believed that the rocks deposited in the Ashby stage 
are younger than those of the Marmor (Chazy group). 
Porterfield stage-——This name is taken from the Porterfield Quarry, 5 miles 
east of Saltville, Maccrady (T.V.A. 218-NW) Quadrangle, Va., and its environs. 
This stage is characterized by the prolific and exotic fauna that floods into the 
Appalachians and blots out and absorbs the Lincolnshire fauna. The Porter- 
field fauna is strongly linked to the Stinchar-Balclatchie fauna of the Girvan of 
Scotland. It is characterized by Christiania, Palaeostrophomena, Isophragma, 
and a host of other restricted genera. In the vicinity of the type area the sequence 
of rocks deposited during this time is not thick, but to the east the section be- 
comes enormously thick. The fauna dies out in the upper part of the Benbolt and 
is replaced in the Wardell by familiar “Black River” types. In northern Virginia 
the Porterfield fauna occupies most of the Edinburg formation and, in modified 
form, characterizes the Oranda formation. 
Wilderness stage.—This stage takes it name from the Wilderness Trail (U. S. 
Highway 58) that parallels the bold Cumberland Front in western Virginia. 
Rocks deposited at this time are well exposed for several miles east of Cumber- 
land Gap and are revealed in their entirety along the railroad at the switch near 
Hagan, Rose Hill (T.V.A. 161-NE) Quadrangle. This stage includes the old 
Black River plus the Rockland and their equivalents. The fauna is especially 
