The Logan Formation is the name given to a
Lower Carboniferous
Lower may refer to:
*Lower (surname)
*Lower Township, New Jersey
*Lower Receiver (firearms)
*Lower Wick Gloucestershire, England
See also
*Nizhny
Nizhny (russian: Ни́жний; masculine), Nizhnyaya (; feminine), or Nizhneye (russian: Ни́ ...
(early
Osagean)
siltstone,
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
and
conglomeratic unit exposed in east-central Ohio and parts of western West Virginia, USA.
Stratigraphy and paleoenvironment
The Logan Formation was named by Andrews (1870) and originally described as a "buff-colored, fine-grained sandstone" above the Waverly Formation and below the Maxville Limestone. Bork and Malcuit (1979) concluded that the Logan Formation was deposited on a shallow marine shelf in a generally
transgressing sea. The age of the Logan Formation has been established as early Osagean (Tn3) by the occurrences of
brachiopod
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, w ...
s,
ammonoids,
conodonts and miospores (Clayton et al., 1998; Matchen and Kammer, 2006).
References
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Image:LoganConglomerateWooster.jpg, Conglomerate in the Logan Formation exposed in Wooster, Ohio, USA.
Image:LoganBrachiopodsWooster.jpg, Brachiopod internal and external molds in the Logan Formation in Wooster, Ohio.
Image:Aviculopecten subcardiformis01.JPG, The bivalve '' Aviculopecten subcardiformis'' from the Logan Formation in Wooster, Ohio (external mold).
Image:LoganFauna011312.jpg, Bivalves (''Aviculopecten'') and brachiopods (''Syringothyris'') in the Logan Formation in Wooster, Ohio.
Image:Logan Formation Cross Bedding Scour.jpg, Cross-bedding and scour in the Logan Formation of Jackson County, Ohio.
Image:Schizodus_medinaensis.JPG, ''Schizodus medinaensis''; a bivalve from the Logan Formation in Wooster, Ohio (internal mold).
Image:Syringothyris01.JPG, ''Syringothyris'' sp.; a spiriferinid brachiopod from the Logan Formation in Wooster, Ohio (internal mold).
Image:Syringothyris bored Wooster Carboniferous.jpg, ''Syringothyris'' external mold with borings; Logan Formation; Wooster, Ohio.
Image:Syringothyris texta Hall 1857 dorsal.jpg, ''Syringothyris texta'' (Hall 1857), dorsal view, internal mold. Lower Carboniferous of Wooster, Ohio.
Image:Helminthopsis01.JPG, ''Helminthopsis'' ichnosp.; a trace fossil
A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...
from the Logan Formation in Wooster, Ohio.
Image:PlatyceratidMississippian.JPG, Crinoid
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
calyx from the Logan Formation in Wooster, Ohio, with a conical platyceratid gastropod (''Palaeocapulus acutirostre'') attached.
Mississippian United States
Carboniferous Indiana
Carboniferous Ohio
Carboniferous West Virginia
Carboniferous southern paleotropical deposits
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