PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 53 
the name that it no longer was of use in that State. Cooper and Cooper there- 
fore proposed the name “Edinburg formation” which is the Chambersburg 
formation minus Oranda and Lowville but including some uncertain layers at 
the bottom: Botetourt and Cybeloides bed. 
Butts believed that the Chambersburg in Virginia was superposed on the 
Athens limestone which he had identified in northern Virginia. Cooper and 
Cooper, however, contend that the Chambersburg and Virginia Athens (now 
Liberty Hall) are facies of each other. This subject is pursued at greater length 
under the Edinburg formation. 
The brachiopods of the Chambersburg formation are listed under the new 
and more restricted units of Craig, and Cooper and Cooper. 
Chatham Hill formation (B. N. Cooper and G. A. Cooper).—This forma- 
tion is named from exposures adjacent to Viriginia Highway 16 along the lower 
northwestern slopes of Walker Mountain. The base of the formation is gen- 
erally not well exposed and is transitional with the underlying black graptolitic 
shales (Rich Valley formation), but the top is prominently defined by the suc- 
ceeding ledges of calcarenite forming the lower part of the Wassum formation. 
The total thickness is about 450 feet in the type section 2 miles south of Chatham 
Hill, Chatham Hill (T.V.A. 218-NE) Quadrangle. The upper 150 feet is cherty, 
dark bluish-gray limestone containing Echinosphaerites, Calliops strasburgensis, 
and Nidulites pyriformis, as well as numerous brachiopods. The lower beds 
are not so fossiliferous but contain Lonchodomas, Robergia, and Bronteopsis. 
Generally just above the thin zone with Nidulites a few beds are crowded with 
gastropods like those in the Peery limestone. The Chatham Hill formation thus 
includes part of the Ward Cove, the Peery, and the Benbolt formations of Taze- 
well County, Va. 
Anisopleurella inaequistriata Cooper L. sublamellosa Cooper 
Bimuria parvula Cooper Mimella bursa (Raymond) 
Camerella immatura Cooper Opikina nasuta Cooper 
C. minuta Cooper Orthambonites bellus Cooper 
Conotreta multisinuata Cooper O. parvicrassicostatus Cooper 
Cristiferina cristata Cooper Oxoplecia multicostellata Cooper 
Cyclospira sulcata Cooper Plectocamara rotunda Cooper 
Ectenoglossa nymphoidea Cooper Scaphorthis virginiensis Cooper 
Glyptoglossa sp. 1 Skenidioides mediocostatus Cooper 
Glyptomena sculpturata Cooper Sowerbyella nasuta Cooper 
Glyptorthis bellatula Cooper S. perplexa Cooper : 
Leptellina bella Cooper Trematis ? parva Cooper 
Correlation of Chatham Hill formation—The brachiopods listed from this 
formation are obviously related to those of the Arline, Effna, Botetourt, and 
Pratt Ferry formations, but in addition some Benbolt types appear. Similarity 
to the Edinburg formation is also evident. 
Chickamauga limestone.—Except for Butts’ use of the name Chickamauga 
in Alabama, this designation has long since passed into disuse. The name was 
so broadly used throughout the Southern Appalachians that it lost its value 
when the Middle and Upper Ordovician limestones and shales were studied in 
