PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 59 
Edinburg formation.—This name was proposed by Cooper and Cooper 
(1946, p. 78) for the Chambersburg limestone of Virginia minus the Oranda. 
The type section was taken near the Shenandoah River, 1.5 miles N. 61° E. of 
Edinburg, Shenandoah County, Va. The lithology of the formation is so variable 
that two facies and one member have been defined to make it better understood. 
The Liberty Hall facies of the Edinburg formation consists of black, slabby con- 
choidally-fracturing limestone that weathers to an ash gray. This facies was 
called Athens by Butts (1940b, p. 159) and was thought by him to pinch out 
under the “Chambersburg” (Butts, 1940b, p. 196) in the vicinity of Edinburg. 
Cooper and Cooper, on the other hand, contend that the Virginia “Athens” is a 
black limestone facies, including some black shale with graptolites, which inter- 
fingers with the Lantz Mills facies of the Edinburg. This member consists of 
cobbly limestone that comes to occupy more and more of the sequence in the 
northern part of the range of the formation. 
At the base of the formation is a granular, often brown-weathering and impure 
limestone containing fossils that constitute a very distinctive assemblage. This 
is the Botetourt formation, which is definitely related to part of the Arline, Effna, 
and Pratt Ferry formations. It is thus now excluded from the Edinburg forma- 
tion and combined with the Cybeloides bed under it. 
Under the probable Boteourt formation at Edinburg dam and along Tumbling 
Run 14 miles southwest of Strasburg, Va., where a superb section is exposed, 
dark slabby limestones appear between the Lincolnshire and the Botetourt. These 
limestones were placed by Butts (1949b, p. 197) in the Chambersburg, but were 
left in the Lincolnshire by Cooper and Cooper. Faunally they are most like the 
overlying Botetourt and are better placed with it. They are called the Cybeloides 
beds after a trilobite which is fairly common in this limestone. 
Cooper and Cooper (1946, pp. 81, 94, 95) note a number of sections in which 
the sequence is well divided between the two facies. In the northern range of 
the formation where the Lantz Mills facies is dominant it is possible to distin- 
guish some elements described by Craig in Maryland and southern Pennsy]l- 
vania. Craig’s Shippensburg formation is mainly composed of Lantz Mills facies 
rocks. The upper massive beds with Camarocladia in the Strasburg section 
undoubtedly belong to Craig’s Mercersburg formation. 
Fossils are numerous in the Edinburg formation, and three major zones can 
be readily recognized: The first is the Cyrtonotella zone, which also abounds in 
Echinosphaerites as well as the zone-naming brachiopod ; the next zone is char- 
acterized by the peculiar Nidulites pyriformis; and the third zone is that of the 
massive limestones with Camarocladia. Brachiopods occur in all the zones; those 
of the Cyrtonotella zone indicate the faunas of the combined interval of Effna, 
Ward Cove through Benbolt, in terms of the Tazewell County sequence. Fos- 
sils taken from the Nidulites zone are most suggestive of an early Trenton (Rock- 
land) level although many genera from the lower beds pass upward through the 
Edinburg, Oranda, and into the overlying Martinsburg (=Salona). No good 
brachiopods have been taken from the Camarocladia beds. 
