Lost River - Karst Information Portal

He then casually and without explanation used
the name Solsberry Formation for these rocks
(Greene, 1911, p 275, 281).
As the term Chester came into common
use and formational names became accepted,
subdivision of the series into groups became
possible. These subdivisions were called “lower,”
“middle,” and “upper Chester” (Cumings, 1922,
pp 408, 515) and were used as groups, sometimes
with capital letters, but were commonly not
expressly called groups. “Chester” became
“Chesterian,” a time and time-rock name that is
appropriately designated a series or epoch but
that is inappropriate as a group name; principally
for this reason Gray, Jenkins, and Weidman
(1960, p 44) adapted two group names earlier
suggested by Cumings (1922, p 514), West
Baden and Stephensport, to replace with some
modification the former usage, lower and middle
Chester. The Kentucky name Buffalo Wallow
was adopted by Gray (1978) in a group sense and
in somewhat modified scope for outcropping
upper Chesterian rocks.
West Baden Group
The name West Baden was originally
proposed as a group name in 1920 by E.R.
Cumings in a letter to Stuart Weller (Cumings,
1922, p 514). The term received no subsequent
use, however, until it was revived in a slightly
modified sense by Gray, Jenkins, and Weidman
(1960, pp 44–48). The group is named for
West Baden, Orange County, and consists in
descending order of the Elwren Formation
(the Cypress Formation in the subsurface), the
Reelsville Limestone, the Sample Formation,
the Beaver Bend Limestone, and the Bethel
Formation. It consists dominantly of gray to
varicolored shale and mudstone and thinbedded
to cross-bedded sandstone. Limestone
in beds of variable thickness is an important but
lesser constituent (Gray, 1962, table 2 and fig. 4).
Total thickness along the outcrop ranges from
100 to 140 feet (30 to 43 meters). Known on
the surface from Putnam County southward to
the Ohio River, the West Baden Group is also
recognized in the subsurface from Parke County
southwestward. Maximum reported subsurface
Stratigraphy and Lithology
thickness is 260 feet (80 meters) in western
Gibson County (Sullivan, 1972, p 11 and pl 3).
A major feature of the West Baden Group is
a southwestward-trending belt about 6 miles (10
kilometers) wide across which the limestones
were not deposited and in which sandstone
dominates the entire thickness of the group.
The West Baden overlies the Blue River Group
(Valmeyeran and Chesterian) conformably
except at a few localities along the clastic belt
where basal sandstone of the West Baden
Group lies disconformably as deep as 50 feet (15
meters) below the normal position of the top
of the Blue River Group (Malott, 1952, p 49).
The West Baden Group is overlain conformably
by the Stephensport Group (Chesterian) or
disconformably by the Mansfield Formation
(Morrowan).
The West Baden Group correlates with rocks
within the lower part of the North American
foraminiferal Zone 16s of Mamet and Skipp
(1971) and within the Visean Series (V3cs) of
European usage. On the basis of its conodont
faunas, the West Baden was assigned to the upper
part of the Gnathodus bilineatus-Cavusgnathus
charactus Assemblage Zone of standard North
American usage by Collinson, Rexroad, and
Thompson (1971).
Bethel Formation and Beaver Bend
Limestone – The Crawford Upland is developed
upon resistant and interbedded limestones,
sandstone, and shales of the West Baden Group
of the Chester Series (Shaver, et al, 1986 pp
43–44 and p 167). The West Baden Group
is generally 100 to 140 feet thick, but is up to
200 feet thick in the clastic belt area. The Paoli
Limestone is directly overlain by 10 to 42 feet of
Bethel Formation (Shaver, et al, 1986, pp 12–13)
that includes gray, clayey shales; wavy bedded,
fine-grained sandstones; and a few thin beds of
coal. The Bethel is the first major non-carbonate
rock unit in the Chester Series of south-central
Indiana. It underlies the Beaver Bend Limestone
which ranges in thickness from less than 1 foot
to as much as 14 feet. It is a coarsely crystalline
to oolitic, reddish to gray limestone. Cave
development in the thin Beaver Bend Limestone
has traditionally been thought to be of minor
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