58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
but interfingers with fine- to medium-grained, platy limestone with beds of dove 
limestone conglomerate. The member ranges in thickness from 40 feet south- 
west of Doylesburg, Pa., to 6 feet at Rockdale, northwest of Williamson, Pa. 
The member is absent in the eastern belts. The Doylesburg member is especially 
characterized by Cryptophragmus and Tetradium cellulosum. Brachiopods are 
few: 
*Mimella sp. 
Zygospira recurvirostris (Hall) 
Correlation of Doylesburg member—Cryptophragmus and Zygospira are a 
combination suggesting correlation with the Witten formation and the Lantz 
Mills facies of the Edinburg formation. 
Dryden formation (B. N. Cooper and G. A. Cooper).—This name is used 
for the combined Benbolt and Wardell formations where they are not separated 
by the Gratton formation. The type section is in the fields on both sides of the 
highway about 1 mile east of Dryden and less than 1,000 feet west of Stallard 
Ford bridge across Powell River, Keokee (T.V.A. 178-SW) Quadrangle, Lee 
County, Va. This formation consists mostly of limestone but may contain con- 
spicuous amounts of shale, as at Rye Cove and Lone Mountain. It attains a 
thickness of 300 to 500 feet. The formation occurs in the western belts of Vir- 
ginia and East Tennessee. It is usually fairly easy to identify the Benbolt or 
Wardell portions of the sequence in the lower and upper parts, respectively, but 
to find the boundary line between the two is more difficult. Usually the zone of 
Dinorthis transversa denotes Benbolt, and the zone of Hesperorthis australis 
indicates the Wardell part. In some instances in the descriptive part of this 
monograph it is stated that the fossils come from Benbolt (or Wardell) although 
they are actually in the Dryden formation. The parts are so clear in these in- 
stances that it is thought better to keep the added refinement. In other instances 
the species are said to be from the Benbolt (or Wardell) part of the Dryden 
formation. 
In the vicinity of Lone Mountain, near Tazewell, Tenn., some mingling of 
Benbolt and Wardell types can be detected. Here Doleroides appears low in the 
section in such a position that it might be interpreted as belonging to the Benbolt 
part of the Dryden formation. The listed fossils show the Benbolt-Wardell 
relationships. 
Chaulistomella brevis (Willard) Opikina speciosa Cooper 
Dinorthis transversoides Cooper O. varia Cooper 
Doleroides irregularis Cooper Petrocrania sp. 1 
D. regularis Cooper Protozyga rotunda Cooper 
Fascifera stonensis (Safford) Rostricellula ovata Cooper 
F. subcarinata Ulrich and Cooper R. rostrata Ulrich and Cooper 
Glyptambonites platys (Butts) R. tumidula Cooper 
Hesperorthis australis Cooper Sowerbyella compacta Cooper 
Mimella globosa (Willard) Strophomena grandimusculosa Cooper 
Murinella muralis Cooper S. inspeciosa Willard 
Oligorhynchia sp. 1 S. medialis Butts 
