A498 PROCEEDINGS OF THE NATIONAL MUSEUM. vou. xxxvv. 
Composite section of Ordovician-Devonian rocks of west Tennessee—Continued. 
| 
| 
wn o- 
| 5) Columnar 
sia | [=| 1AeT] 
S| # section Description. 
a | (Lobelville). 
Bh fe | 
| | Bob formation. 
Conchidium zone (15/). : 
Massive crinoidal to argillaceous limestone with few fossils, species 
of Conchidium being most characteristic. 
Dictyonella zone (30). “8 
Blue clay and shales crowded with brachiopods. Dictyonella gib- 
bosa, Gypidula roemeri, Merista tennesseensis, Uncinulus tenneés- 
seensis, and Wilsonia saffordi are among the more common or 
m5! characteristic forms. 
( 
Uncinulus zone (30/), 
Gray massive limestone at top and red shaly strata in lower two 
thirds. Large examples of Uncinulus stricklandi are numerous 
and the most noticeable fossils. 
Pee Beech River formation... 
Eucalyptocrinus zone. 
| Fossiliferous, dark blue shales and thin cherty limestone, becom- 
| ing yellowish toward top. Hucalyptocrinus milliganae and other 
erinoids characteristic fossils. 
ail 
S 
H 
S 
et 
2 Troostoerinus zone. 
ra) Blue shales witha bed of compact limestone 5 or more feet thick 
q at the base and a similar limestone band developed in the mid- 
S dle part. Troostocrinus reinwardti abundant and characteristic 
5 of this division. 
A 
1067 6” | 
Coceoerinus zone. 
Blue to white shales and shaly limestone readily disintegrating 
into clay. Fossils abundant with Coccocrinus bacca as the diag- 
nostic form. 
Dixon formation. 
Red to purple shales and clayey limestones with occasional layers of 
white argillaceous rock. Fistulipora hemispherica the only abun- 
dant fossil. 
