MAYSVILLE WEST
Roadcut
A very large exposure of
Upper Ordovician rocks occurs ~2 miles northwest of the small city of
Maysville, northeastern Kentucky. This is the Maysville West
roadcut (although it is known by other names as well). Maysville West occurs
just on the Kentucky side of the large Harsha Bridge over the Ohio River, along
either side of the relatively new Rt. 62/68 bypass around Maysville (see
map). The road cuts through Jersey Ridge, and was formerly known as
Rt. 3071. This cut is excellent for seeing stratigraphy, but also has
fantastic fossil collecting.
GPS of cut: 38° 40.407' North, 83°
47.830' West.
The Maysville West roadcut
is the NE-SW trending whitish-gray streak just above the center of this
satellite photo. The dark blue curving feature is the Ohio River. (Satellite photo provided by
TerraMetrics & Google Earth)
Maysville West has nice
exposures of the middle and upper Kope Formation (Edenian Stage, lower
Cincinnatian Series), the Fairview Formation, and the Bellevue
Limestone (both lower to middle Maysvillian Stage, middle Cincinnatian
Series). The Bellevue Formation is also referred to as a member of the
lower McMillan Formation/Grant Lake Formation.
The Kope occurs at the
bottom of the cut and is generally shale-rich. The Fairview occupies the
middle portions of the cut, and is roughly 50-50 limestone & shale.
The Bellevue occupies the top portions of the cut, and is dominated by limestone
beds.
Looking ~N.
The photos above & below
show the northwestern side of the Maysville West roadcut. The top wall in
the pics (above the top visible bench) is Bellevue. In general, the next
three walls down are Fairview Formation. The wall seen at the bottom
right corner of the pics is the top of the Kope Formation. The formation
contacts do not coincide with bench levels, however.
The thick, light-colored
limestone bed in the upper Fairview Formation here is a seismite
horizon. It has highly convoluted bedding and contains limestone
breccia. It has been interpreted as a portion of the ancient Ordovician
seafloor that was significantly disturbed by a paleoearthquake. Seismites
have been identified throughout Kentucky in the Middle and Upper Ordovician.
The Maysville West roadcut
has produced some fantastic fossils, including rare edrioasteroids, “pockets”
of glyptocrinid crinoid heads, cyclocystoids (including at least one unnamed
& undescribed species), large Rusophycus carleyi burrows (made by Isotelus
maximus asaphid trilobites), etc., etc. Maysville West is a great
place for obtaining “star bryozoan” specimens (Constellaria florida) and
large Platystrophia ponderosa orthid brachiopods. Horizons of
large trepostome bryozoan masses (called “reefs” by at least one bryozoan
worker) occur in the Bellevue Limestone near the top of the cut.