Richmond Group in Ohio and Indiana. — Nickles. 213, 
tectecl. This may be due, however, to the very limited ex- 
posures showing the superposition of one upon the other. In a 
road side cut at Dayton, Ohio, both formations are seen 
essentially horizontal, but there is a sudden change from a blue 
shale to a compact, white, heavy-bedded limestone. The upper 
surface of the clay is irregular but the irregularity is nowhere 
more than a few inches. At Madison, Indiana, the base of this 
division is a layer abounding in massive specimens of corals, 
mainly Columnaria alvcolata (Goldfuss), [=Fai'istclIa stellata 
Hall], and Calopoecia cribriformis (Nicholson). This bed is 
local in its development. At Versailles the lower layers contain 
a large amount of Tetradium minus Safford. At Richmond, 
Ind., at the top of the Whitewater beds are found two 01 three 
feet of strata in which Strephochoetus richmondensis (Miller) 
is most prolificaUy developed. These layers probably mark the 
transition from the Whitewater to the Madison. As only a few 
feet more are exposed at Richmond, — in a cutting on the C. R. 
& M. R. R., just north of the bridge over the Whitewater 
river, — having several layers of limestone developed with the 
shale, and no other exposures of these or higher strata were 
seen in this vicinity, the writer does not feel entirely sure that 
these strata really belong to the Madison division. At Day- 
ton, Ohio, the lowest layers do not seem to differ much from the 
uppermost in the Whitewater beds, but the general lithological 
character of the Madison is very different from that of the 
Whitewater. In the vicinity of Dutch creek in Clinton county, 
Ohio, two or three heavy layers of limestone are found at the 
base of the Madison. 
Fossils are very much less abundant in this division than in 
in the preceding. At Madison they are so securely imbedded in 
the rock that they are not easily obtained. At the top of the 
bed at Madison there is a stratum, — the Murchisonia hammelli 
bed of Foerste, — with a distinctive fauna, discovered in 1889 
by Mr. George C. Hubbard, including Lophospira hammelli 
(Miller), Holopca hubbardi Miller, Cyrtoccrina madisonense 
(Miller), Cyrtoceras sp., Orthoceras n. sp., Strcptclasma sp., 
Hebertella occidentalis (?) (Hall), Byssonyehia robust a 1 ?) 
(Miller). Ptcrinca sp., Cypricarditcs haincsi Miller. Clidophor- 
us sp., Liospira inieula (Ulrich), and Labcchia ohiocnsis Nich- 
olson. In Elkhorn creek fine large specimens of Hebertella sin- 
