J'ariatioits of the Ordoi'ician of huUaiia. — Focrstc. 89 
diminution in thickness bc.c:ins much farther north than Ten- 
nessee. According to Hayes and Ulrich*, the Utica is absAit 
in the Richmond and London (|uadrangles on the eastern side 
of central Kentucky. Recently Dalniaiiclla mnltisccta has 
been found nine miles north of Richmond, al. Clays Ferry, in 
beds overlying strata referred to the top of the Trenton. 
The Lorraine diminishes in thickness from 290 feet in the 
neighborhood of Cincinnati to 260 feet near Madison, Indiana. 
In south-central Tennessee, its thickness does not exceed 100 
feet. Along the Tennessee river, at Clifton, a section, three 
and a half feet thick, may belong to the top of the Lorraine. 
It contains Dinorthis rctrorsa, a species formerly believed to 
be restricted to the Warren bed, but this fossil has been found 
recently in Indiana also in the upper half of the W^aynesville 
bed. Elsewhere in the Tennessee river valley of western Ten- 
nessee the Lorraine certainly is absent. 
The Richmond diminishes in thickness from 300 feet in the 
southern part of Franklin county, Indiana, to 115 feet at Mar- 
ble Hill, 60 miles southwest. In central Kentucky, much thin- 
ner sections are known. In southern Tennessee its thickness 
does not exceed 40 feet and averages about 20 feet. 
3. Di)iiiiiution in Thickness of the SiibdiTisio)is of the 
Lorraine. 
The diminution in thickness of the Lorraine is accompan- 
ied, of course, by a diminution in thickness of certain of its 
various subdivisions. 
No decrease in thickness is noted in case of the Bellevue 
and Warren beds within the limits of Indiana. The Bellevue 
bed is the chief Platystrophia lynx horizon of southern Indiana. 
At Cincinnati, where Platystrophia lynx is rare at this horizon, 
the thickness of the Bellevue bed is about 20 feet. Near Mad- 
ison, in Indiana, its thickness varies from 20 to 24 feet. South- 
ward, in Kentucky, the lower Platystrophia lynx or Bellevue 
bed forms one of the most constant horizons. The Warren 
bed has a thickness of 61 feet at Lebanon, in Ohio. At Mad- 
ison, in Indiana, the thickness of the Warren bed certainly 
equals and probably exceeds this amount ; the distance from 
the top of the Mount Auburn layers containing Platystrophia 
* Folio 95, Columbia, Tenn., 190;{ , 
