52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Centre Hall member of Nealmont formation.—The original spelling of 
this name by Field (1919, p. 417) was incorrect. Kay altered the spelling to 
conform, as above, with that of the county and village. Although Field pro- 
posed the name as a formation, Kay has lowered its rank to one of the members 
of his Nealmont formation. The Centre Hall member is distinguished from the 
underlying Oak Hall member by its thinner-bedded and more shaly character. 
A fairly imposing list of brachiopods has been identified from the member, but 
some of the identifications seem incorrect. The member has been placed in the 
early Trenton and correlated with part of the Rockland formation. The list of 
brachiopods does not wholly support this contention. Valcourea has not been 
seen this high elsewhere, nor has Parastrophina hemiplicata been seen below 
the Oranda. The identification of Sowerbyella punctostriata is probably incorrect. 
The brachiopods identified are: 
Ancistrorhyncha sp. O. wagneri (Okulitch) 
*Doleroides pervetus (Conrad) Parastrophina hemiplicata (Hall) 
*Glassia sp. Rhynchotrema sp. 
*Glyptorthis sp. cf. G. bellarugosa (Conrad) *Sowerbyella punctostriata (Mather) 
Hesperorthis tricenaria (Conrad) Strophomena sp. cf. S. filiterta (Hall) 
*Leptaena sp. cf. L. charlottae Winchell and Strophomena sp. 
Schuchert = Limbimurina *Valcourea sp. cf. V. loricula (Hall) 
*Opikina inquassa (Sardeson) Zygospira recurvirostris (Hall) 
O. minnesotensis (N. H. Winchell) 
Chambersburg formation.—This, like some other thick formations of the 
Appalachians, has been revised and reorganized to such an extent that the name, 
when used at all, really takes the form of a group term. This is now especially 
true of the Chambersburg formation. It was first revised by Butts, then by 
Cooper and Cooper, and finally by Craig, who completely split up the old forma- 
tion and did not use the name Chambersburg. 
As originally defined the formation included about 150 feet of calcilutite at 
the base which was correlated to the Lowville formation. The Chambersburg 
above this basal part was thought to belong to the Black River. Butts (1940b, 
p- 195) excluded the Lowville part from the formation. In 1946 Cooper and 
Cooper defined the Oranda formation and separated it from the top of the Cham- 
bersburg formation. In 1949 Craig made an exhaustive study of the Middle 
Ordovician rocks above the Stones River group in south-central Pennsylvania. 
His studies led to a complete revision of the formation. Butts’ Chambersburg 
was divided into two formations: The Shippensburg and Mercersburg forma- 
tions. Each of these formations in turn was subdivided into three and two 
members respectively. Craig’s divisions have not been carried into Virginia and 
West Virginia, but some of his formations are certainly there. In the vicinity of 
Strasburg, Va., it is possible to recognize part of the Shippensburg formation, 
and the upper massive beds just below the Oranda formation suggest some 
part of the Mercersburg formation. This subject is discussed further under the 
Edinburg formation. 
In Virginia, Cooper and Cooper felt that the removal of the Lowville and 
Oranda from the Chambersburg formation so altered the stratigraphic value of 
