RT66:IL Mighty Mississippi's Chain of Rocks EarthCache

To log this cache:

1. Take a picture of your face with the rock ledge in the background. This is best taken from the coordinates.

2. Go up on the bridge (you can park free near the Illinois side) and email the following items from the sign near the center of the bridge on the south side. The river supports how many species of fish and how many species of mussels? What is the cubic feet of water per second that roughly flows out to the Gulf of Mexico? What is the first line of the quote from Mark Twain about his book “Life on the Mississippi.”?

LOGS NOT MEETING THE CRITERIA WILL BE DELETED.

Be sure to get the virtual cache GC2258 located on the bridge while you are there.

There is parking access to the bridge from both sides but it is recommended to park on the Illinois side as there is better security and car break-ins have been reported on the Missouri side. On 06/12/09, cacher BlueBeadMan reported: "...the Illinois side of the river is just as dangerous as the Missouri side, it just doesn't get the same publicity. You find just as much broken glass, beer bottles, evidence of criminal activity, and things like used condoms on the IL side as you do on the MO side. Perhaps the famous murder case which occurred on the middle of the bridge and was tried in MO gives the MO side a worse reputation. Who knows...the IL side is more secluded and thereby more prone to criminal activity than the MO side..."

Originally a motor route, it now carries walking and biking trails over the river. The chain of rocks stretch for seven miles immediately to the north of the city of St. Louis. The Mississippi's water, narrowed by these rock ledges, rushes through this reach at speeds of 12 feet per second, roaring down a decline of 11 feet in seven river miles.

Both the strange 22-degree turn in the bridge and the Chain of Rocks owe their existence to glaciers. During the last ice age, the Mississippi River was re-routed from its original channel in soft river sediment to its present channel over resistant, mainly limestone, bedrock. The river has yet to wear down the bedrock and this feature is still a rough spot in the river. If the bridge had been built straight, the engineers would have had to choose between two problematic routes. One route would have put the bridge in a location where it couldn't have been solidly founded on bedrock. The other route would have posed problems to river navigation by not allowing barges to line up with the current, possibly causing them to collide with the bridge. It served as a compromise between geological and navigational concerns.

Other changes in the course of the river have occurred because of earthquakes along the New Madrid Fault Zone, which lies between Memphis and St. Louis. Three earthquakes in 1811 and 1812, estimated at approximately 8 on the Richter Scale, were said to have temporarily reversed the course of the Mississippi. The settlement of Reverie, Tennessee was cut off from Tipton County, Tennessee, during the 1811 and 1812 earthquakes and placed on the western side of the Mississippi River, the Arkansas side. These earthquakes also created Reelfoot Lake in Tennessee from the altered landscape near the river.

The rapids seen just to the south of the bridge are actually water spilling over the 2,925-foot low-water River Dam 27, the first permanent rock-fill dam across a major river in the United States. This dam was built in 1960 to insure adequate depths over the lower sill of the old Alton Locks that was 12.5 river miles upstream.

From the Illinois side of the bridge, signs marked "HISTORIC ROUTE 66 SPUR" take travelers to the Illinois side of the bridge and a "HISTORIC ROUTE 66" sign marks the Missouri side of the bridge. The Gateway Arch is visible downriver, and immediately downstream from the bridge, two water intakes for the St. Louis Waterworks are visible. In the mid 1990s, a Bigfoot monster truck drove over the "chain of rocks" located just downstream from the Chain of Rocks Bridge.

A below water dam was built across the Mississippi River below the Chain of Rocks to keep the river level high enough at the upstream end of the canal to provide adequate flows/levels for navigation within the canal. Just to the north of the Chain of Rocks Bridge, the Missouri River flows into the Mississippi. The site where these two rivers come together (confluence) was once located on private property, but is now open for all to see thanks to the Missouri Department of Conservation. Several trail routes to the confluence are available from the conservation area parking lot. The shortest route is about six miles round trip on flat land.

Confluence of the Mississippi and Ohio Rivers is located at Cairo, Illinois. The Missouri River flows from the confluence of the Jefferson, Madison, and Gallatin to the Mississippi River. Taken together, the Jefferson, the Missouri, and the Mississippi form the longest river system in North America. If measured from the source of the Jefferson at Brower's Spring, to the Gulf of Mexico, the length of the Mississippi-Missouri-Jefferson combination is approximately 3,900 miles, making the combination the 4th longest river in the world. The uppermost 207 miles of this combined river are called the Jefferson, the lowest 1,352 miles are part of the Mississippi, and the intervening 2,341 miles are called the Missouri.

It is a unique opportunity to be able to see two of the world’s largest rivers combining. The water in the Missouri River flows about 3,740 miles from its headwaters in Montana through the Mississippi River and into the Gulf of Mexico. This combined waterway is the world’s third longest with the Nile and Amazon ranking first and second respectively. This feature also owes its existence to the continental ice sheets covering North America during the last ice age. Before this time, the Missouri River used to flow through Canada and into the Hudson Bay. The Missouri River’s modern day course is a good rough indicator of the southernmost advance of the continental ice sheets.

The Mississippi River is the second longest river in the United States, with a length of 2,340 miles from its source in Lake Itasca in Minnesota to its mouth in the Gulf of Mexico. The longest river in the United States is a Mississippi tributary, the Missouri River, measuring 2,540 miles. The Mississippi River is part of the Jefferson-Missouri-Mississippi river system, which is the largest river system in North America and among the largest in the world: by length, 3,900 miles, it is the fourth longest, and by its average discharge of 572,000 cu ft/s, it is the tenth largest river.

The Mississippi River runs through 10 states and was used to define portions of these states' borders. The middle of the riverbed at the time the borders were established was the line to define the borders between states. The river has since shifted, but the state borders of Wisconsin, Iowa, Illinois, Missouri, Kentucky, Arkansas, Tennessee, and Mississippi have not changed; they still follow the former bed of the Mississippi River as of their establishment. The source of the Mississippi River is Lake Itasca, 1,475 ft above sea level in Itasca State Park located in Clearwater County, Minnesota.

The uppermost lock and dam on the Mississippi River is the Upper St. Anthony Falls Lock and Dam in Minneapolis, Minnesota. Above the dam, the river's elevation is 799 feet. Below the dam, the river's elevation is 750 feet. This 49-foot drop is the largest of all the Mississippi River lock and dams. By the time the river reaches St. Paul, Minnesota, below Lock and Dam #1, it has dropped more than half its original elevation and is 687 feet above sea level. From St. Paul to the Gulf of Mexico the river elevation falls much more slowly and is controlled and managed as series of pools created by locks and dams.

The Mississippi River empties into the Gulf of Mexico about 100 miles downstream from New Orleans. Measurements of the length of the Mississippi from Lake Itasca to the Gulf of Mexico vary somewhat, but the United States Geological Survey's number is 2,340 miles. The retention time from Lake Itasca to the Gulf is about 90 days. The Mississippi River discharges at an annual average rate of between 200,000 and 700,000 cubic ft/s. On average, the Mississippi has only 9% the flow of the Amazon River but is nearly twice that of the Columbia River and almost 6 times the volume of the Colorado River.

Many of the works of Mark Twain deal with or take place near the Mississippi River. One of his first major works, Life on the Mississippi, is in part a history of the river, in part a memoir of Twain's experiences on the river, and a collection of tales that either take place on or are associated with the river. Twain's most famous work, Adventures of Huckleberry Finn, is largely a journey down the river.

The Mississippi River probably has more nicknames than any other river. Mississippi means "large river" to the Chippewa Indians. It is called Big Muddy (also commonly used for the Missouri), Big River, Body of a Nation, El Grande, El Grande de Soto, the Father of Waters, the Gathering of Waters, the Great River, the Mighty Mississippi, the Muddy Mississippi, Old Man River, etc. This Earthcache is dedicated with much love to my dad, John Haslock, for knowing all of those nicknames & for taking me to Cairo, Illnois when I was young - even if I didn't even undertsand then why he chose such an odd place to go on vacation. I am still not sure why we drove a couple hundred extra miles to visit an old slave house, but, besides my dad having some similarities to Clark Grizwold, I am sure that destination had a purpose as well.