418 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
BEECH RIVER FORMATION. 
As indicated previously, the lowest beds of the Brownsport group 
furnish most of the crinoids of the late Niagaran of West Tennes- 
see. To this formation the name Beech River is applied from the 
conspicuous exposures along Beech River in Decatur County. The 
weathering of these beds gives rise to the most conspicuous of the 
West Tennessee glades. Their strata are almost exclusively fine 
shales of a gray, yellow, or bluish color, but weathering into a white 
clay. These shales are generally present where their proper place in 
the section is exposed; indeed, they form the most widely spread di- 
vision of the late Niagaran. Their fauna is also the best known of 
any of the Niagaran divisions, probably because most of the well- 
known crinoids and blastoids from West Tennessee are derived from 
them. Coccocrinus bacca, Troostocrinus reinwardti, and Eucaly pto- 
crinus milliganae are particularly abundant, and each was found to 
be characteristic of a certain zone. Numerous outcrops of these 
shales may be seen in the general area between Perryville and Clifton, 
but particularly fine exposures are found at Brownsport Furnace, 
thence northward to Perryville, and at numerous localities along 
Beech River. The Brownsport Furnace section has been given on a 
preceding page; the sections along Beech River are essentially the 
same, but the best exposed and most clearly defined section of the 
Beech River formation is found at the large glade about 2 miles 
south of Perryville. 
Section two miles south of Perryville, Decatur County, Tennessee. 
Decatur limestone. In large boulders covering formation below__~---~~ — 
‘Beech River formation. 
Eucalyptocrinus zone. 
Fine bluish fossiliferous shales in Ne lower part and yellow 
shales increasing in their yellow color and fossiliferous character 
toward the top. Hucalyptocrinus milliganae is not uncommon, 
while Lampterocrinus tennesseensis, Callicrinus ramifer, Eu- 
calyptocrinus ventricosus, Marsupiocrinus tennesseensis, and 
many other species of the same class are occeasionally found. 
Troostocrinus is a rare fossil and the specimens are larger and 
more slender than the typical 7. reinwardti of the beds below_ 20 
Troostocrinus zone. 
Yellowish shales with numerous typical Troostocrinus rein- 
wardti and Caryocrinus bulbulus less common-____---_-------- eine © 
Gray, Shaly limestone forming a bench on the glade____________ 1-3 
Very fossiliferous, bluish, and whitish shales, becoming tinged 
with yellow: toward: the ito ps ee eer ee oe a Sse ene en 11 
Coeccocrinus zone. 
Rather shaly limestone, much more resisting than shales above 
and below. This limestone forms a well-marked bench sepa- 
rating the Coccocrinus zone below and the Troostocrinus zone 
AD OVE cr SG Bit ay RATER URE ah a rep en Seco 
