Jan., 1914.] Richmond Beds of the Cincinnati Group. 
231 
minus, Calapoecia cribriformis, Hebertella sinuata, Platystrophia 
acutilirata, Ischyrodonta truncata, Losphospira bowdeni, Liospira 
sp., Bellerophon sp., Endoceras sp., Primitia glabra, Isochilina 
subnodosa, Tetradella simplex, etc., etc. 
The Tetradium minus is rather scarce at Madison, but is 
common 1' above the second Columnaria reef toward Hanover, 
and again above the mollusc layers 3 miles north. At the locality 
five miles north it is very abundant through T of blocky, shaly 
limestones, immediately above the limestones representing the 
second reef. From here on this Tetradium horizon is very con¬ 
stant, and occurs whereever the rocks have been exposed as far 
north as Liberty, Ind. and as far toward the east as Oxford, 0. 
A mile east of Liberty, where the Oxford pike crosses Hannah’s 
Creek, the Tetradium is scattered abundantly through the whole 
4' 9" of Saluda rocks. Beneath are exposed 3' of shales and thin 
limestones with much the same fauna as is carried by the same 
strata at Laurel. 
North of Liberty only three miles, at the last long exposure 
on Richland Creek, the Saluda strata have almost lost the Tetrad¬ 
ium, and are distinctly shaly except at the top, where they end 
in two heavy limestones, the lower one 1 ' 2" thick and very irregu¬ 
lar, the top one 10" thick and more even. The top stratum is 
composed largely of fossil "hash,” and in this are water-worn 
Rhyncotrema capax, etc. It occurs at this level to within four 
miles of Oxford. Immediately above it are the characteristic 
Whitewater strata and fauna. 
The lower shales are partly replaced by evenbedded limestones 
along Elkhom Creek, and at the quarries along the Whitewater 
River south of Richmond are represented by limestones indistin¬ 
guishable from those below. But the top stratum is still heavy 
and characteristic. 
While perhaps not strictly the equivalent of the second Colum¬ 
naria reef, this Tetradimn reef developed immediately above it 
and replaced it further north. Outside the Madison region it 
bases the Saluda type of strata. 
Practically whereever this reef is seen it is closely associated 
with a fauna similar to the one three miles north of Madison. 
Sometimes this fauna is above the reef or in it, but usually is 
beneath. Near Versailles the Dystactospongia is especially abun¬ 
dant and ju.st below it are found, besides the molluscs listed above, 
Ptilodictya magnificia, Monticulipora epidermata, Leptaena 
rhomboidalis, Agelacrinus cincinnatiensis, and Lichas sp. 
At Oxford, Ohio, the first incursion of the Whitewater fauna is 
preserved in the 3' of Trochoceras shales, and among the clams 
are such characteristic forms as Byssonychia grandis, B. richmond- 
ensis, Ischyrodonta elongata, I. truncata Opisthoptera casei, 
Ortonella hainesi, and Whitella obliquata. 
