76 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
tain fault in southern Tennessee, Georgia, and Alabama, the Lower Ordovician 
(Canadian limestones and dolomites) are succeeded by red beds and buff earthy 
limestone 50 to 175 feet thick, which resemble closely the Blackford red beds 
of Virginia and Tennessee and parts of the Attalla formation of Alabama. The 
basal layers of the Long Savannah formation contain detrital chert and some 
minor quartz sand. There are indications that the formation possibly ranges as 
high as Peery and Rob Camp formations. It is also possible that the base, al- 
though lithologically identical with the basal Blackford beds, is considerably 
higher in the column than the latter. No fossils have been taken from the forma- 
tion. The type section is exposed along the Mahan Gap Road, but the name is 
taken from Long Savannah Creek just northeast of Snow Hill, Snow Hill 
(T.V.A. 212-NE) Quadrangle. 
Loysburg formation.—As described by Kay (1944, pp. 1-6), this formation 
in central Pennsylvania consists of two members: The “Tiger-striped” and the 
Clover. The formation lies between the Lower Ordovician Bellefonte formation 
and the Hatter formation. The “Tiger-striped” consists of buff-weathering dolo- 
mite which penetrates and channels the Bellefonte limestone. In addition to this 
lithology are limestones, laminated dolomites, and thin beds of ostracode-bearing 
limestone. This part of the sequence has never been studied in detail, but it is 
possible that the dolomites and interbedded limestones between the Clover and 
Lower Ordovician are to be correlated with the Row Park formation. The Loys- 
burg, like the Blackford of Virginia, may be of different age in different places. 
The Clover member is a sublithographic limestone mentioned under that head- 
ing above. No brachiopods have been reported from the Loysburg formation. 
Mahan formation.—(B. N. Cooper and G. A. Cooper.) This name is pro- 
posed for 200 feet of ribbon-banded to thick-bedded dove-gray calcilutite, the 
lower half of which is characteristically studded with plates and nodules of black 
chert. The upper part of the formation is even-bedded Tetradium-bearing cal- 
cilutite with numerous shaly interbeds containing Pionodema and Ancistro- 
rhyncha. The Lower beds contain species of Strophomena, like those in the 
Ridley limestone of the Central Basin of Tennessee, and S. inspeciosa Willard. 
The Mahan formation succeeds a body of red dolomitic mudstone and inter- 
bedded buff earthy limestones, the Long Savannah formation. The top of the 
Mahan is defined at the type locality by a Moccasin-type red mudstone—one of 
several red intercalations in a thick succession of ribbon-banded Camarocladia- 
bearing limestones. The type section is along Mahan Road, Snow Hill (T.V.A. 
112-NE) Quadrangle, about 1,900 feet west-northwest of the intersection with 
Tennessee Highway 60, Hamilton County, Tenn. The Mahan formation is be- 
lieved to include mainly beds of Benbolt and Pierce-Ridley affinities, but possi- 
bly Peery and Rob Camp formations of southwestern Virginia are represented 
in the lower part. (See Benbolt and Pierce-Ridley formations for lists of fos- 
sils.) The Tetradiwm-bearing beds of the Mahan are lithologically indistinguish- 
able from Hurricane Bridge formation as developed at Hagan, Va., and Speed- 
well, Tenn. 
Marcem formation (B. N. Cooper and G. A. Cooper, new formation) .— 
