This is a complete list of current bridges and other crossings of the Ohio River from the mouth at the Mississippi River at Cairo, Illinois to the confluence of the Allegheny and Monongahela Rivers at Pittsburgh, Pennsylvania .
12-399: (crosses the river entirely within the state of Kentucky at this point) ( Falls of the Ohio ) The source of the Ohio River is at the confluence of the Allegheny River and the Monongahela River ( 40°26′31″N 80°00′50″W / 40.44194°N 80.01389°W / 40.44194; -80.01389 ) at Pittsburgh, Pennsylvania . Download coordinates as: Falls of
24-493: A new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya ). Later agoniatitid ammonoids would die out in the Taghanic event in the upper middle Givetian . Goniatite ammonoids would give rise to further ammonoid orders, thus starting ammonoid dominance of marine fossils in further periods until their end at
36-532: A river such as Niagara Falls . Still, the falls provided a singular, dramatic, and daunting obstacle to navigation on this important inland waterway . The first locks on the river, the Louisville and Portland Canal completed in 1830, were built within a bypass canal constructed to provide year-round navigation of the river. The falls were later largely covered by the McAlpine Locks and Dam , built by
48-762: A section of the area in Indiana became the Falls of the Ohio State Park . An interpretive center is open throughout the year. Prior to modification for industrial and navigational purposes, the Falls of the Ohio spanned the entire width of the Ohio River. Native Americans and early European explorers heard the crisp roar of the Ohio River crashing down the cascade falls more than 10 miles away. The rock unit in which
60-426: A significant area of the fossil-rich Devonian limestone rock is still left exposed, and is accessible to visitors today. The best time for visitation is during the low water season of the Ohio River between August and October. Removal of fossils is prohibited. The shallowness of the falls provided a favored crossing point for bison in pre-settlement times and, later, an easy crossing for Native Americans. In 1990,
72-434: Is located at the Falls of the Ohio, which was the only navigational barrier on the river in earlier times. The falls were a series of rapids formed by the relatively recent erosion of the Ohio River operating on 386-million-year-old Devonian hard limestone rock shelves. Louisville, Kentucky , and the associated Indiana communities— Jeffersonville , Clarksville , and New Albany —all owe their existence as communities to
84-881: Is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan , 35 centimetres (14 in) above the contact with the Madmon Formation . In North America the Emsian Stage is represented by Sawkill or Sawkillian time. During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which
96-494: The Army Corps of Engineers. The taming of the Ohio River at the falls, with the attendant reduction in local flow velocity, has of late led to the covering over of the fossil beds by large and increasing quantities of low-velocity effluvia: although an impediment to viewing the fossils, this action serves to protect the portions of the falls covered over by sediment and therefore temporarily immune to direct weathering. However,
108-667: The Devonian Period, the region lay at the bottom of a shallow inland sea about ten degrees north of the equator in the supercontinent of Euramerica . Emsian The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It
120-759: The Ohio The Falls of the Ohio National Wildlife Conservation Area is a national, bi-state area on the Ohio River near Louisville, Kentucky , in the United States , administered by the U.S. Army Corps of Engineers in partnership with the Indiana Department of Natural Resources . Federal status was awarded in 1981. The falls were designated a National Natural Landmark in 1966. The area
132-709: The falls are formed is referred to as the Jeffersonville limestone . The limestone formed approximately 387 to 380 million years ago during the Emsian Age (in the latest part of the Early Devonian Period) and the Eifelian Age (Middle Devonian). The exposure is unique—large and diverse tabulate corals and rugose corals are exposed in lifelike positions. Brachiopods and bryozoans are also present, as are gastropods (snails). During
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#1732765018745144-420: The falls, as the navigational obstacles the falls presented meant that late-18th-century and early- to late-19th-century river traffic could benefit from local expertise in navigating the 26-foot (7.9 m) drop made by the river over a distance of two miles (3 km). In its original form, the falls could be characterized more as rapids extending over a length of the river, than as a point-like discontinuity in
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