7O SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
contains Leperditia in abundance and was originally assigned to the Black River. 
Elsewhere the Jacksonburg (R. L. Miller, 1937) attains a thickness up to 300 
feet and is transitional to the overlying Martinsburg formation. 
The lower division of the Jacksonburg contains Receptaculites occidentalis 
Salter as well as Leperditia. Brachiopods found in the Lower Jacksonburg are: 
Camarella inornata Weller = Idiospira inornata (Weller) 
Dalmanella subaequata (Conrad) = Pionodema subaequata (Conrad) 
Lingula sp. = Skenidioides sp. 
Rafinesquina alternata (Emmons) = R. trentonensis (Conrad) 
Scenidium anthonensis Sardeson = Skenidioides sp. 
Strophomena conradi Hall and Clarke 
Strophomena sp. 
This list suggests assignment to lower Trenton rocks such as the Guttenberg 
member of the Decorah because of the presence of Rafinesquina and Pionodema. 
Correlation with the Nealmont of Pennsylvania, the Collierstown formation of 
Virginia, and the Rockland of New York and Ontario is also possible. 
Brachiopods from the upper division are: 
Dalmanella subaequata (Conrad) = Pionodema subaequata (Conrad) 
*D. testudinaria (Dalman) = Paucicrura sp. 2 
Dinorthis pectinella (Emmons) 
Lingula riciniformis Hall 
Orbiculoidea lamellosa (Hall) 
Orthis tricenaria Conrad 
Parastrophina hemiplicata (Hall) 
*Platystrophia biforata (Schlotheim) = Oxoplecia ? 
*Plectambonites sericeus (Sowerby) 
Plectorthis plicatella (Hall) 
*P. (Austinella) whitfieldi (N. H. Winchell) 
Rafinesquina alternata (Emmons) 
Reuschella americana Cooper 
*Rhynchotrema dentata (Hall) 
*R. inaequivalvis (Castelnau) 
Schizocrania filosa (Hall) 
Strophomena conradi Hall and Clarke 
*Strophomena incurvata (Shepard) 
Zygospira nicolleti (Winchell and Schuchert) = Protozyga nicolletti (Winchell and 
Schuchert) 
Z. recurvirostris (Hall) 
Correlation of upper Jacksonburg formation.—This list is difficult to interpret 
because of unlikely species listed, but presence of Reuschella and Parastrophina 
are links to Oranda and Salona. 
Kauffman member of Mercersburg formation.—This formation has its 
type section in the railroad cut 24 miles southwest of Marion, Pa. The mem- 
ber consists of 168 feet of platy, bedded limestone lying conformably on the 
Housum member of the Mercersburg formation and disconformably below the 
Oranda formation. Craig (1949, p. 734), who named the member, states that it 
thins to the northeast of the type section. In the western belts the member can 
be recognized only in a few sections containing Mercersburg metabentonite No. 2. 
