PART ad CHAZYAN AND RELATED BRACHIOPODS—COOPER gI 
Cooper and Prouty (1943, p. 868) for argillaceous, dark-gray, nodular-weather- 
ing limestone, often with a dark, bluish-gray coarse-grained limestone at the 
base. These coarse-grained rocks are local in their development. The member 
is variable in thickness but attains 100 feet. It is named from exposures along 
the northwest base of East River Mountain south of Shannondale on U. S. High- 
way 19. Cooper and Prouty (1943, p. 870) report the following brachiopods: 
*Camerella quadriplicata (Willard) 
*Camarella cf. C. varians Billings 
Campylorthis sp. = Chaulistomella sp. 
Dinorthis quadriplicata Willard = D. transversa Willard 
*Glyptorthis bellarugosa (Conrad) 
Mimella melonica (Willard) = M. globosa (Willard) 
*Opikina “minnesotensis” (N. H. Winchell) 
*Plectorthis cf. P. exfoliata Raymond 
Piychoglyptus sp. (probably Bellimurina sp. True Ptychoglyptus not seen this high by the 
writer) 
*“Rafinesquina”’ cf. R. deltoidea (Conrad) = Opikina 
*“Rafinesquina” sp. = Opikina 
Sowerbyella sp. 
Strophomena tennesseensis Willard = Rhipidomena tennesseensis (Willard) 
*Zygospira” cf. Z. acutirostris (Hall) = Sphenotreta cuneata Cooper ? 
Shippensburg formation.—This formation with type section in the railroad 
cut 24 miles southwest of Marion, Pa., was defined by Craig (1949, p. 717). 
In the eastern belts of south-central Pennsylvania the formation attains its great- 
est thickness of 416 feet. Here it is divided into two members: Pinesburg and 
Fannettsburg. In the western belts the formation is thinner, but there a third 
member, the Doylesburg, appears above the Fannettsburg. The Shippensburg 
formation consists of five lithologic types: Dark-gray, fine-grained cobbly lime- 
stone ; fine-grained, dark-gray and evenly bedded limestone ; medium to coarse 
calcarenite; interbedded dark-gray, medium-grained limestone; and calcilutite 
pellet conglomerate and dove calcilutite. The brachiopod content of the formation 
is discussed under the individual members. 
Snyder member of Benner formation.—Described by Kay (1944, p. 15) 
for a calcilutite attaining a thickness of 110 feet in central Pennsylvania; this 
member forms the lower part of the Benner formation. Conglomerates with white 
limestone pebbles are diagnostic of the member, which has not yet yielded 
brachiopods. 
Speers Ferry formation.—This name was used by Ulrich (1939, p. 106) 
in a correlation chart, but no description was ever published to validate it. On 
that chart the formation appears in a column headed Clinton and Pearisburg 
troughs. It is placed between the Ottosee below and the Pierce formation above. 
According to present understanding of Appalachian stratigraphy, this position 
is impossible. The Speers Ferry may have been designed for the beds now 
called Wardell. 
Stones River group.—This is a group term (see C. W. Wilson, 1949) 
which, after some refinements, was made to contain four formations in ascend- 
