Conor Watkins' Ozark Mountain Experience

Field Trip Guide to the
Geology, Scenery, And History of The Salem Plateau of the Ozarks
–In The Buckhorn, Dixon, and Rolla Areas
For The Fall 2003 MVOR hosted by MSM Spelunkers at Shriners Club, Buckhorn, MO - Oct 3-5, 2003
By Conor Watkins, University of Missouri - Rolla

Stop 3: The Devil's Elbow Area

The town of Devil’s Elbow is considered to be one of the highlights of a tour on Missouri Route 66.  The area is home to the Big Piney River and its scenic bluffs, Sheldon’s Market which doubles as the Devil’s Elbow Post Office,  The Elbow Inn Bar And Grill which originally opened in 1929, and last but not least, the original Route 66 steel truss bridge across the river.

The town’s picturesque setting has led film producers from around the world to record parts of their movies and TV shows in the area.  Upon viewing the guest registry at Sheldon’s Market, one will discover that many of the visitors are from overseas.  Although Devil’s Elbow is a sleepy Ozark town, the fame of Route 66 and its scenery attract visitors from worldwide.  The visitor to Devil’s Elbow will also notice others slowly driving Route 66 taking both still and moving pictures, no matter the time of day or week.  The view of the 200 foot tall bluffs of Gasconade dolomite visible from the bridge was once described as being one of the "Seven Scenic Wonders of Missouri" in literature put out by the Missouri Planning Commission during the 1930's-40's.

This scenic view of the Big Piney is easily observed from the 1923 truss bridge in
Devil’s Elbow via a 20-minute drive from Rolla.  This view of towering 200 foot
Gasconade dolomite bluffs was once listed by the State Planning Commission as
one of the "Seven Scenic Wonders of Missouri."

Postcard (date unknown) - back reads "Big Piney River with its cool sparkling
waters, plentiful in game fish, studded with rugged mountains, is a natural paradise."

The scenic area is located in Pulaski County just northeast of Ft. Leonard Wood.  The Big Piney River in Devil’s Elbow was once used as transportation to float timber downstream, a practice that continued into the early 1900’s.  A sharp bend (elbow) in the Big Piney used to hang up the timber, leading to tremendous jams, giving the area its name.  At the time, the area was known for rough characters and hard drinking tie rafters.  The town has kept its name although the tie rafters are long gone.

The "Devil's Elbow" of the Big Piney used to wreak havok for those floating
ties down the river.

The Devil’s Elbow of the Big Piney is an entrenched meander that was preserved when the Ozarks were uplifted and the river was rejuvenated.  Prior to the uplift, the Ozarks had been eroded down to a flat plain, known as a peneplain, common to old age erosional settings.  As with the Mississippi and other old age rivers, the river had slowed and was meandering across a wide floodplain.  When the region was once again uplifted, the river downcut from its existing position, preserving the meandering course.  Such entrenched meanders are common to rivers throughout the Ozarks.

The Devil's Elbow of the Big Piney River is an excellent example of an
entrenched meander on an Ozark stream.

During the 1930's a proposal to dam the Gasconade River at four locations (Richland, Arlington, Vienna, & Rich Fountain) was considered to provide flood control, generate power, and aid in river navigation on the Missouri and Mississippi Rivers.  If built, the Arlington Dam would have backed up the Big Piney, inundating the town of Devil's Elbow and much of the surrounding area, including Boiling Spring.  This dam was to be part earthfill and part mass concrete in design.  Before construction could begin, federal funds became tied up by the Great Depression and World War II, delaying the dam projects.  No large dams were ever constructed in the area, allowing both the Gasconade and Big Piney Rivers to be classified as free flowing rivers.  There are seven rivers fitting this classification in Missouri today.  At one time, there were plans to dam all seven of these rivers.

Around the time the dams were being proposed, nearly all of the original two lane section of Route 66 was upgraded and paved with concrete.  Since Devil's Elbow was to be inundated by the dam, the stretch of Route 66 through the area was left alone.  To this day, there is no concrete in the portion of original Route 66 running through Devil's Elbow with the exception of the Devil's Elbow Bridge deck over the Big Piney.

Cross section of the proposed Arlington Dam in its earthfill portion.
(U.S. Army Corps of Engineers, 1932)

Cross section of proposed Arlington Dam at the power house.
Click on either of the above images for more extensive plans.
(U.S. Army Corps of Engineers, 1932)

This section of a Phelps County tourism map published jointly by the
Missouri School of Mines and the Rolla Chamber of Commerce during
the 1930's (exact date unknown) shows where the Arlington Dam was
to be located.

Partial map showing area inundated by the proposed Arlington Reservoir.
Click map to see all four reservoirs.

We will enter the area from the west and pass Shanghai Spring (locally known as Blue Spring), a large spring feeding into the Big Piney River.  This spring is located on private property and posted with “No Trespassing,” but it can be clearly viewed from the road.  It originates from a blue pool located adjacent to a scenic bluff.  The spring branch flows under both the road on which one drives to view the spring and the U.S. Army Railway spur through culverts before flowing into the Big Piney River.  This spring will not be included in any stops but will be passed along the road.  Slow down and admire.

Shanghai Spring, also known as Blue Spring, is on private property but is easy to view from the road.

Shanghai Spring and a others along the nearby Big Piney River receive much of their recharge water from nearby Fort Leonard Wood (FLW) and are impacted by pollution sources at the Army base.  Three solid waste landfills, a sewage treatment plant, an old pesticide building, and an old laundry and dry cleaning shop are located in the recharge area of Shanghai Spring.  Unfortunately water quality has suffered due to these activities.  Several types of volatile organic compounds (VOCs), chlorinated hydrocarbons, pesticides, and constituents of sewage effluent are being discharged by the spring.  It appears that some of the landfills at FLW are leaking leachate into the groundwater and that other chemicals were leaked by the old dry cleaning shop and pesticide building.  The Shanghai Spring recharge system has a fast response rate after rains and some chemicals increase in concentration soon after large rainfalls.  This indicates that chemicals are trapped in the unsaturated zone above the water table and are picked up by water percolating through the ground.  The karst aquifer in this region is very complex and more analysis is needed to determine the exact sources and solutions to the problem.

The first stop in the Devil’s Elbow area will be about a quarter mile east of Shanghai Spring, where a unique deposit of polished gravels with a glassy texture is located.  Although the agent that created these shiny pebbles is no longer present, many glinting rocks remain.  It is possible that this area was once part of a cave stream or spring outlet that is no longer present.  Some current cave systems and spring outlets contain similar polished rocks and a large deposit of similar material is located near the outlet of Bennett Spring near Lebanon, MO.  Perhaps that site was once an outlet for the spring.  Running water containing fine cave clays and silts can act like jeweler’s rouge to polish rocks.  There is a definite relationship between the size of the rocks and their degree of polishing.  The smaller rocks tend to be much more polished anbd rounder than the larger fragments, indicating that the smaller rocks were polished for an extended period of time.  This hillside deposit has had a hard time in recent years.  The soil is poor and unable to support vegetation, allowing the material to simply wash away.  Most of the polished rocks are now gone.

The polished rocks are positioned near a pen and ruler for scale.  The smaller
stones have a much higher degree of polish, indicating that they were tumbled
longer than the larger specimens.

Closeup photo of two polished rocks

While at this site, notice the deep residual soils in the adjacent roadcut immediately to the west.  These soils contain clays and cherts leftover from the in-place weathering of the bedrock.  100 feet or more of such deposits were uncovered during the construction of nearby Ft. Leonard Wood and the Norfork Dam in Arkansas.  The cut of deep residual soils is one of the best in the area.  Pieces of chert left behind during the weathering occasionally come loose and roll down the slope and onto the road as seen here.  There may or may not be a connection between this deposit of soil and the adjacent polished rocks site but water flowing through a cave/spring system could acted to help weather the surrounding material.

The polished rocks site is just east of this exposure of deeply weathered soils
in the vicinity of the grove of cedar trees near the truck.  One can see that
this weathered bluff is susceptible to small rockfalls as several have rolled
onto the road.

The next stop in Devil’s Elbow is the scenic view of the Big Piney River at the old bridge.  The shear bluffs present are in part due to the geology of the area.  One will notice that the forests atop the bluffs, especially in its upstream portions, contain many shortleaf pine trees, giving the river its name.  The bluffs are capped by Roubidoux sandstone, which weathers to produce acidic soils, allowing the pines to thrive.  The Roubidoux sandstone also weathers at a slower rate than the underlying Gasconade dolomite, allowing it to serve as a protective caprock over the weaker dolomite below.  If the sandstone layer were not present, the Gasconade Formation would likely have weathered to a much more subdued profile and not the sheer, scenic bluffs seen along the Big Piney and other streams in the central Ozarks.  The high bluffs near Devils Elbow offer opportunities for those who like to rock climb and rappel.

Notice that the pines are growing atop the bluffs in the Roubidoux sandstone
and not the Gasconade dolomite below.  The Gasconade dolomite would have
weathered to a more subdued profile without the Roubidoux Formation
to serve as a caprock.

The contact of the Roubidoux and Gasconade Formations is present at the top of the bluffs overlooking Devil's Elbow.  Due to the resistance of the Roubidoux formation, several small overhanging ledges of Roubidoux sandstone are present along the bluffs at Devil's Elbow and others along the Big Piney.  One rock protrusion of sandstone above Devil's Elbow is called the "Devil's Tongue" by older generations and "Lizard Rock" by those who are younger.  The older folks also refer to it as another portion of the Devil's anatomy present below the belt.

Devil's Tongue/Lizard Rock is a protruding ledge of Roubidoux sandstone.

Another rock prominence in the bluffs above the Big Piney in Devil's Elbow is known as the Devil's Sugar Bowl.  When viewed straight on, this formation resembles a large bowl with a conical mound of material protruding above the rim.

Red dot shows the Devil's Sugar Bowl.

Postcard (date unknown) - back reads "An interesting rock formation
overlooking the Big Piney River at Devil's Elbow, MO."

The Big Piney River originates near Cabool, MO and flows north to join the Gasconade near Jerome.  It flows through remote parts of Missouri between Cabool and Houston.  After flowing north past Houston the Big Piney enters the Mark Twain National Forest and Ft. Leonard Wood.  River accesses and good roads leading to the Big Piney are few and far between.  Some access points are provided by the National Forest Service, the Missouri Department of Conservation (MDC), and private businesses.  Most accesses are not located near heavily populated areas.

Perhaps its remote location is the main reason that the Big Piney remains so undeveloped, scenic, and peaceful, for it is a beautiful Ozark river.  The river is kept relatively cool all summer since it is fed by various springs along its course.  These springs also help keep the water levels consistent and allow the river to be floated during dry periods.  High, scenic bluffs rim certain stretches of the River.  Those used to floating other Ozarks streams may notice that the water of the Big Piney is not quite as clear and carries a greenish hue.  This color is due to the abundance of plankton, a microscopic organism nourished by nutrients washed into the river from the surrounding landscape.  Most of these nutrients are from the soil of the region, which happens to be slightly more nutrient rich than most Ozark soil.  The abundance of plankton has led to a rich and diversified river food chain, making the Big Piney an excellent location to fish for rock bass, small mouth bass, and other species of fish.  The abundant plankton by no means gives the river a dirty or unpleasant appearance.  Instead, it gives the river an almost surreal look and makes an excellent location for photographs.

One may also notice the abundant gravels in the bed and along the banks of the Big Piney.  Although this gravel is now common to all but a few Ozark streams, it was not always present in as large of an amount.  When the Ozarks were logged and farmed in the past, extensive erosion of the land clogged the rivers with sediment.  Although many of these practices have ceased and the finer sediments have washed away, there is still a large amount of gravel in the river.  The construction of Ft. Leonard Wood in the early 1940’s is also thought to have been responsible for some of the erosion and gravel deposition in the Big Piney.

After looking at the view from the top of the bridge, one might want to venture underneath the bridge to see how the 1923 structure has fared over the years.  The bridge was constructed by use of hot rivets in 1923 to serve Missouri Route 14.  When Route 66 was laid across the country in 1926, the pre-existing bridge served as a convenient and cost saving alignment over the Big Piney River.  As war spread around the world in the late 1930’s, the United States government began to prepare for the worst while still hoping for peace.  Existing military installations were improved and many new bases were constructed around the country.  Ft. Leonard Wood in Pulaski County, MO was built in a matter of months to serve as an Army training center.

It was immediately obvious that the narrow winding road and bridge through Devil’s Elbow were inadequate due to many large trucks going to and from the nearby fort.  In 1941 a straighter and flatter four-lane stretch of Route 66 was built just to the north of Devil’s Elbow.  Roadcuts were used to keep grades reasonable.  At 90 feet, the Hooker Cut, just east of Devil’s Elbow, was the deepest roadcut in Missouri and one of the deepest in the country when it was excavated.  After this time, the town remained relatively isolated as travelers passed by on the new stretch of road.

Postcard from soon after Hooker Cut was excavated
(exact date unknown - circa 1940's).
"HOOKER CUT ON NEW HIGHWAY 66
between Rolla and Waynesville.  One of the deepest
rock cuts in the U.S."

Summer 2002 view of Hooker Roadcut
Around 60 years of weathering and growth including kudzu
have seriously altered the appearance of the Hooker Cut.

When the Interstate system was commissioned in 1956, the 1940's stretch of Route 66 through the area served as Interstate 44 until a more modern highway could be constructed.  It wasn't until the early 1980's that the present day section of I-44 through the area was built.

Since this time, maintenance of the old bridge has been less of a priority to state and federal governments and Pulaski County has limited funds for highway repairs.  Two bridges, one on the 1941 stretch of Route 66 and the I-44 bridges, cross the Big Piney River and give motorists alternate routes around the Devil’s Elbow Bridge.

During the 1970’s, it was noticed that the concrete bridge piers were cracking and starting to spread apart.  Steel plates were attached to the top of the piers and pressed against the concrete by using tensioned steel cables in order to confine the concrete and hold the piers intact.  This was the last major maintenance performed on the old bridge.

This bridge pier has been confined with steel plates
wrapped with cables to help prevent further deterioration.

Upon driving across the bridge, it appears to simply need sandblasting and a paint job.  Surface rust is visible on the steel but the structure is sound.  Unfortunately it is a whole different scene underneath the bridge. The paint has deteriorated and severe rust has set in where moisture collects, especially at the south end of the bridge.  Rust has completely eaten through several gusset plates (plates used to attach different structural members) and stabilizing lateral members under the road deck.  The lateral members serve to keep shaking and vibration due to wind and traffic on the bridge to a minimum.  These members are simple steel angles (members with an L-shaped cross section) that are placed diagonally at various points underneath the bridge.  A few of these structural parts are now completely detached from their intended connections underneath of the bridge and are hanging freely.  Parts of the stabilizers or their gusset plates have simply rusted through completely.  Perhaps the most serious structural issue is with a support beam underneath the bridge on the southwest side.  The beam consists of two standard channels (members with a C-shaped cross section) riveted back to back to roughly form an I-beam cross section.  One of the standard channels has rusted nearly completely though, so this beam is only able to support one half of its designed load.

Although the Devil's Elbow Bridge appears to simply need a good sandblasting
and paint job from above, the scene underneath is a different story.

This gusset plate is nearly rusted through.


This lateral stabilizing member has completely rusted through
and is no longer attached.

Perhaps the most serious structural problem is the rust
that has nearly eaten away half the lower cord
under the bridge.

It appears that much of this rust has been encouraged by an expansion joint that allows water to drain directly onto the structure below.  Since this part of the structure remains wet longer than areas exposed to the sun above, it is more subject to corrosion.  The original 1923 concrete deck on the old bridge is also in need of repair, although it doesn’t appear as critical as the steel structure.  The road surface is pitted in places and other sections are noticeably crumbling.  This damage is probably due to two factors that are common in the Missouri Ozarks.  Bridges in the area are subject to frost action, especially when the temperature frequently freezes and thaws, as it does during Missouri winters.  When water freezes within concrete or rock, it opens cracks, allowing more water to enter on the next freeze cycle.

Alkali-aggregate reactions are another common problem with concrete in the Ozarks.  These reactions occur due to conflicting chemistry within the concrete mix itself and are due to the geology of the Ozarks.  Most cement is alkali (basic) in chemistry and will react with acidic aggregates.  Silica based aggregates produce a mild acid as they weather.  The dolomite bedrock of the Ozarks is notorious for containing nodules of chert.  As the rock weathers, it leaves behind nodules of chert, as these more resistant to weathering.  These pieces of chert tend to wash down into creeks and rivers where they form the gravel bottoms and bars so common to Ozark streams.  Chert is a silica-based rock and produces mild acids as it weathers in the presence of water.  This is especially a problem when chert contains opaline quartz.  Many Ozark cherts do contain this mineral form.  Chert aggregates are commonly used in the Ozarks because they are plentiful and easy to obtain.  It isn’t hard to scoop gravel out of a river to use in concrete mixes.  Those doing this are usually unaware of the chemical reaction that lies ahead.  Although this reaction is slow and can take many years to cause noticeable damage, it is something that can and should be avoided by carefully selecting quality aggregates.

As acids from the weathering of the chert aggregate react with alkali compounds from the cement, a paste is formed.  This paste expands and cracks concrete, much as water does when it freezes.  The pitting on the road surface has allowed water to pool.  Since water is an important player in both freeze thaw damage and alkali-aggregate reactions, these small pools of water work to degrade the concrete.  Both freeze-thaw and alkali-aggregate reactions work together in a synergistic manner to positively reinforce the effects of each process.  This allows more water to infiltrate the concrete, causing a “Catch 22” cycle of damage.  Some concrete has spalled off, exposing rusting re-bars underneath.  Both processes could be slowed if a sealant to reduce the infiltration of water was applied to the deck.

In June 1999, MODOT inspected the bridge and noted some of the problems described above.  The inspection report suggested removing debris underneath, to prevent the retention of moisture, and to give the bridge a paint job.  Neither task has been completed.

The next and last stop in Devils Elbow will allow one to view the area from atop the bluffs.  This stop takes the viewer to the edge of the high bluffs overlooking Devil’s Elbow and the surrounding area.  One can get an excellent perspective of the Devil’s Elbow itself, the town, and the roads through the area.  In addition, the view is spectacular.

Views of the Devil's Elbow during winter.


The 1923 Devil's Elbow Bridge as seen from the overlooking bluffs.


The town of Devil's Elbow as seen from the bluffs.


All three bridges over the Big Piney in the vicinity of Devil's Elbow can be seen from the
bluff overlooking the area during the winter when the leaves are down.  The 1923 Devils
Elbow Bridge may be seen along with the 1940's Route 66 Bridge (arched concrete
structure) and the 1980's I-44 bridge (green girders & crossing semi-trailers visible)
in the far distance.
Additional view of Devil's Elbow Bridge

While viewing the Devil's Elbow area from atop the bluffs, one might want to take note of the Gasconade/Roubidoux Formation contact.  The overlying Gasconade Formation tends to form overhanging ledges along the bluffs.

The Gasconade/Roubidoux Formation Contact - The more resistant Roubidoux
Formation weathers at a slower rate than the underlying Gasconade Formation,
forming overhanging ledges and protecting the dolomite below.

DIRECTIONS - To Devil's Elbow:

To get to Devil’s Elbow from Boiling Spring, return to Hwy 28 via PP and headsouth to I-44.  Cross over I-44 and take a right at the T-junction. This road is Hwy Z (old Route 66).  Follow to Tulsa Rd. and turn left, following signs to the Willard Quarry.  After passing the quarry, turn left at the junction and drive across the low water crossing.  Continue to drive, paralleling the U.S. Army Railway tracks and, Shanghai Spring will appear on the left.  The stop at the polished rocks is also on the left about 1/4 mile after the spring just past an exposure of deeply weathered residual soils.

The polished rocks site is just east of this exposure of deeply weathered soils
in the vicinity of the grove of cedar trees near the truck.

After stopping at the polished rocks site, continue to follow the road east until it comes up a hill and returns to Hwy Z farther to the east.  This is part of the four lane stretch of Route 66.  Most of the pavement on this stretch is original from 1944 and is in remarkable condition for its age.  Turn right and follow for short while.  Turn right almost immediately at Teardrop Rd., which is the original 1920’s Route 66.  A scenic pullout on the right offers an interesting view of the Big Piney River and a bridge and trestle serving the U.S. Army Railroad.  This will included as a stop if time permits.

After passing the pullout, the road will descend into the town of Devil’s Elbow.  Parking to observe the area is available in the town near Sheldon’s Market, which is off to the right just before crossing the bridge.  After leaving this location, drive over the old bridge (if you do so dare!) and continue past the Elbow Inn Bar and BBQ Pit.  Turn right as soon as the four lane stretch of Hwy Z is rejoined.  Follow a short while and turn right again at Teasley Rd.  The Hooker Cut can be observed at the turn and during the drive up the hill.  Although this doesn’t look like a spectacular cut by today’s standards, it was quite an engineering feat in its day.  After viewing the lookout, return to Hwy Z and turn right (east) and follow to Hwy J.  Turn left and follow across I-44.

The curbs along this stretch of Route 66, especially those along the left lane, are sharply inclined towards the roadway.  This practice was common at the time this highway was constructed since it was believed that such a design would keep cars from going off the road.  This curb design was discontinued once it was discovered that the inclined curbs actually caused cars to overturn.

Kudzu, an aggressively growing vine, clings to the cliffs and makes for a pretty drive during Missouri’s growing season.  This vine is an alien species from Japan and has taken over parts of the southern U.S. Luckily the cold winters of Missouri keep its growth in check.  This short section of road eventually runs into St. Robert.  Many consider this to be one of the more scenic stretches of road in Missouri.  It is unfortunate that the modern day interstate, completed in the early 1980's, now completely bypasses this stretch of Route 66.  This four-lane stretch of road seems very empty now that most traffic passes by on I-44.

(C) 2004 by Conor Watkins