PART I CHAZYAN AND RELATED BRACHIOPODS—-COOPER 39 
East Tennessee interfingers with platy sandstones which themselves often con- 
tain fine graptolites. (3) Calcareous shales, often yellow-weathering, characterize 
the Hogskin member of the Lincolnshire formation and most of the Benbolt 
formation. These shales are reminiscent of the Sevier but do not contain much 
sand and are usually more calcareous than the Sevier. Furthermore, they are 
often characterized, particularly the Benbolt as exhibited in Raccoon Valley, by 
layers of limy cobbles. 
Limestones.—The western belts of the Appalachians are predominantly com- 
posed of limestone which interfingers with the finer clastics of the medial belts. 
(1) “Marble” is a term incorrectly applied to the calcarenites or coarse lime 
sands which are a prominent feature of some of the belts, particularly those in 
East Tennessee passing through Knoxville, but also prominent from Eidson 
southwest to Luttrell along Clinch Mountain. These masses have caused con- 
siderable difficulty in correlation because of their similarity of lithology and 
fauna regardless of position. The marbles are generally composed of echinoder- 
mal material, broken shells, and other organic debris. In some instances, as at 
Porterfield Quarry, McNutt Quarry, Tillson Mill, and a few other places, the 
calcarenites are associated with bioherms or “reefs” probably formed by bryo- 
zoans. A special type related to the calcarenites is the shell breccia which forms 
beds usually less than a foot, but occasionally several feet, thick. One or more 
beds of this type occur in the Witten formation and generally contain the peculiar 
Cryptophragmus antiquatus. This fossil is not confined to this lithology but is 
commonest in it. Many other types of fine or coarse detrital limestone are present 
in the Appalachians, but they do not generally form large masses. (2) Calcilu- 
tites, massive or thin bedded, are one of the commonest facies of the Appalachians 
and form most of the western belts. Indeed, this type of rock is so thick and so 
like the Lowville of New York that the New York name was applied to nearly 
the entire sequence along the Cumberland Front regardless of fossils which indi- 
cated otherwise. The name Lowville as used in the Appalachians was truly a 
facies term. The calcilutites form thick masses in the so-called Mosheim facies, 
which occurs at several levels in the Lenoir formation, and similar bodies occur 
at other levels. The fact that Mosheim-type calcilutites appeared frequently at 
the base of the Lenoir gave credence to the idea that it was a continuous sheet 
of rock rather than a facies. However, in one quadrangle in Virginia the Mos- 
heim was mapped at three different levels, a clear indication that it is a facies 
and not a formation. (3) The black limestones of Virginia as typified by the 
Liberty Hall facies, and the Whitesburg formation of Tennessee are a special 
type of calcilutite. These are often heavy bedded, but may be the reverse, and 
are generally poorly fossiliferous. In some places they interdigitate with black 
shales, as in Catawba Valley. (4) The cobbly limestones, which are generally 
sandy or silty, are an eastern phase of limestone prominent in several belts in 
East Tennessee and also in the Lantz Mill facies of the Edinburg formation. 
The best example of this type is seen in the Arline formation and its lateral 
equivalent, the Athens formation. In East Tennessee this rock is often leached 
of its lime, when it appears to be a sandy shale, occasionally graptolitic, occa- 
