48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
tella, Isophragma, Paurorthis, Perimecocoelia, and Rhipidomena. This is the 
last appearance of Cyrtonotella, Isophragma, Perimecocoelia, and Rhipidomena. 
Wardell elements are: Fascifera, Murinella, Pionodema, Rostricellula. The 
Benbolt is not the earliest appearance of any of the genera just mentioned ex- 
cept Pionodema, but these genera are abundant in the Wardell and fairly char- 
acteristic of it, except for Pionodema. The assemblage that appears in the Arline 
is thus terminated in the Benbolt, and thereafter a marked faunal change takes 
place. After the Benbolt the faunas contain elements of the Trenton such as 
Strophomena, Doleroides, Zygospira, and Pionodema. 
Benner limestone.—This formation (Kay, 1944, p. 15) is composed of well- 
bedded limestone 14 to 190 feet in thickness. It is present throughout central 
Pennsylvania and southeastward to the western belts of Cumberland Valley. The 
type section is at Union Furnace although the name is from a township in Centre 
County. The formation is composed of two members; the lower one is the 
Snyder limestone and the upper is the Stover limestone. These two names should 
be consulted for details. 
Hallina lirata Cooper is recorded from the undivided formation. The Benner 
is regarded as a correlate of the Witten formation of Virginia and Tennessee. 
Ben Hur formation.—This formation was proposed by Miller and Brosge 
(1950) and consists of yellowish-gray limestone and yellow to buff, drab mud- 
stone about 180 feet in thickness. The middle portion of the formation is marked 
by a few limy layers with Camarocladia. This formation was named for an ex- 
posure in the L. and N. RR. cut west of Ben Hur, Ben Hur (T.V.A. 170-NE) 
Quadrangle, Va. The following brachiopods are known: 
Pionodema minuscula (Willard) 
Strophomena sp. 
Zygospira sp. 
Blackford formation.—Butts proposed this name for a series of conglomer- 
ates, red beds, gray shales, dolomites, and chert beds which overlie the Knox 
dolomite at Blackford, Russell County, Va. These beds were overlain by a 
vaughanitic limestone or calcilutite identified by Butts as Mosheim limestone. 
The Blackford was originally defined as a facies of the Murfreesboro formation 
which was thought to overlie the Knox and underlie the Mosheim. 
Subsequent work on the Blackford indicates that it does not correlate with 
the Murfreesboro limestone of the Central Basin of Tennessee. Cooper and 
Prouty (1943, p. 862) therefore graduated Butts’ term to their Cliffield forma- 
tion where it formed the lowest member. The member as described by Cooper 
and Prouty is a composite containing separable units. The Blackford therefore 
has undergone further revision. The upper “blocky chert’’ was separated as the 
Elway formation (B. N. Cooper, 1945b, p. 42). In some areas the Blackford 
contains calcarenites with Rostricellula that are recognizable as, and referable 
to, the Lenoir formation. These, too, have been named. Blackford has thus be- 
come a name of little use. It may be applied to basal shales, dolomites, and 
conglomerates, but these are often demonstrably of different age in different 
belts. The name is therefore of little use in Appalachian stratigraphy in any 
