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. Federal status was awarded in 1981. US Grant Bridge in Portsmouth, Ohio with Ohio River and Scioto River tributary on right. ... The official logo of Louisville Metro Louisville (usually pronounced ; see Pronunciation below) is Kentuckys largest city and the 16th largest city of the United States. ... United States Army Corps of Engineers logo The United States Army Corps of Engineers, or USACE, is made up of some 34,600 civilian and 650 military men and women. ... The U.S. Constitution, adopted in 1789 by a constitutional convention, sets down the basic framework of American government in its seven articles. ... 1981 is a common year starting on Thursday of the Gregorian calendar. ...

Overview

The area 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 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 drop made by the river over a distance of two miles. In its original form, the Falls could be characterized more as rapids extending over a length of the river, than as a pointlike discontinuity in a river such as Niagara Falls. Still, the Falls provided a singular, dramatic and daunting obstacle to navigation on this important inland waterway. The Devonian is a major division of the geologic timescale that extends from the end of the Silurian period (360 million years ago (mya)) to the beginning of the Mississippian subperiod of the Carboniferous (408. ... Limey shale overlaid by limestone. ... State nickname: Bluegrass State Other U.S. States Capital Frankfort Largest city Louisville Governor Ernie Fletcher Official languages English Area 104,749 km² (37th)  - Land 102,989 km²  - Water 1,760 km² (1. ... State nickname: The Hoosier State Other U.S. States Capital Indianapolis Largest city Indianapolis Governor Mitch Daniels Official languages English Area 94,321 km² (38th)  - Land 92,897 km²  - Water 1,424 km² (1. ... Jeffersonville is a city located in Clark County, Indiana. ... Clarksville is a town located in Clark County, Indiana. ... New Albany is a city located in Floyd County, Indiana. ... (17th century - 18th century - 19th century - more centuries) As a means of recording the passage of time, the 18th century refers to the century that lasted from 1701 through 1800. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... The Horseshoe Falls, one of the three Niagara Falls. ... A waterway is any navigable body of water. ...

The first locks on the river were built on a bypass canal there to provide year-round navigation on the river. The Falls were then largely covered by the McAlpine Locks and Dam, built by 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 of the fossils, this action serves to protect the portions of the Falls covered over by sediment and therefore temporarily immune to direct weathering. However, 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 is between August and October. Removal of fossils is prohibited.

Because of the shallowness of the river at the Falls, it was a favorite crossing point for bison in pre-settlement times. Binomial name Bison bison Linnaeus, 1758 The American Bison (Bison bison), also called Buffalo, is a bovine mammal that is the largest terrestrial mammal in North America. ...

In 1990, a section of the area in Indiana became the Falls of the Ohio State Park. An interpretive visitor center is open throughout the year. 1990 is a common year starting on Monday of the Gregorian calendar. ...

Geology

The rock unit in which 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).

During 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. A supercontinent is a mass of land comprising more than one continental core, or craton. ... Euramerica (also known as Laurussia) was a minor supercontinent created in the Devonian by the collision of Laurentia and Baltica. ...

External links

• Falls of the Ohio State Park (http://www.fallsoftheohio.org/)
• McAlpine Dam (http://www.hq.usace.army.mil/hq_streams/mcalpine.htm) (U.S. Army Corps of Engineers)