Wednesday, August 9, 2017


Continued from previous post.
General geologic map, provided by the South Dakota Geological Survey with my annotations, showing the location of Chamberlain on the Missouri River (C) at the boundary of Cretaceous rocks and glacial drift.  Spearfish is located at the BH symbol at the north end of the Black Hills.
So, it was off to South Dakota and a little down time in one of my favorite locations in the Black Hills—Spearfish.  My Blog is full of postings about the Hills and the list is too long for notice here.  As stated many times, I have a very soft spot in my heart for South Dakota since my two-year stay at the University of South Dakota (1965-1967).  Wow, it has been 50 years since graduation on that hot August Day.

A domed Spearfish Peak, elevation 5796 feet, rising from Northern Black Hills just south of Spearfish, South Dakota.
Spearfish is often touted as the City of Peaks, especially the surrounding Crow Peak, Spearfish Peak and Lookout Mountain.  The first two are Tertiary intrusions (described in posts September 5, 2013 and August 14, 2014) while the latter is a much lesser peak composed of late Paleozoic? and early Mesozoic rocks.  The city of Spearfish sits in a valley of eroded fine grained red rocks, a few limestones, and prominent white gypsum layers termed the Spearfish Formation (type locality).  The exact age of the Formation is unknown but evidently spans the Paleozoic (Permian Period)—Mesozoic (Triassic Period) boundary.  This time was a period of the great Paleozoic continental seas withdrawing from North America (or what we would later call North America) and rocks of the Spearfish indicate deposition from nearshore marine grading into terrestrial deposition along shorelines to restricted circulation and drying marine waters and a variety of others.  This conglomeration of rocks are often called “red beds” by geologists and are found in many similar time zones across the central and western United States.
Redbeds of Permian age, with a cap of massive gypsum, cropping out in northwest Oklahoma.  These beds are similar in age and composition with the Spearfish Formation.
In areas of relief these red beds are easily eroded and in a locality like the Black Hills (domal uplift) a valley is created and often is termed the “race track” or red valley as it essentially encircles the Hills.  I-90 follows the race track from Rapid City north through Spearfish and then northwest around the “top” of the Hills to around Sundance, Wyoming.  It is a prominent geomorphic feature. 
Diagram of the Black Hills uplift showing the Red Valley (Race Track) of easily erodible red shales. This is a well known diagram by A. N. Strahler that has appeared in numerous publications and articles.
At Spearfish, Lookout Mountain (4452 feet) seems to be part of the east escarpment of the race track and is about 800 feet higher than the city. The slope of the Peak is composed of redbeds of the Spearfish Formation and includes a prominent white resistant bed of gypsum.  On top of the Spearfish, in ascending order, are the Gypsum Springs Formation (Middle Jurassic), the Sundance Formation (mostly Middle Jurassic), the Morrison Formation (Upper Jurassic), and the Lakota Formation (Upper Cretaceous) (Lisenbee and others, 2013). The shale beds in these upper layers are sometimes difficult to identify due to erosion and it is tough for me to distinguish between massive gypsum beds of the Spearfish Formation and the overlying Gypsum Springs Formation.  The yellow sandstone below the summit is probably the Hulett Member of the Sundance Formation.
Lookout Peak exposing redbeds and a prominent gypsum bed of the Spearfish Formation.
In terms of geologic interest there is not much really exciting about Lookout Mountain; however, the Peak is the original home of the Thoen Stone.  What stone you shout?  Well, the Thoen Stone with its inscriptions on a slab of sandstone.  The original owners of the Stone were the Thoen brothers who evidently quarried sandstone on the Peak for use in the building industry.  According to numerous stories the slab was found several feet below the surface of the surface in 1887.  The boys noted the Stone had tantalizing inscriptions, written in cursive no less, on both sides.  The front side noted that in 1833 seven prospectors came to the Black Hills:
Came to these hills in 1833 seven of us
Ezra Kind
G.W. Wood
T. Brown
R. Kent
Wm. King
Indian Crow
All dead but me, Ezra Kind. Killed by Ind.
ians beyond the high hill. Got our gold June 1834
The rear inscription: Got all the gold we could carry. Our ponies all got by the Indians. I have lost my gun and nothing to eat and Indians hunting me

So, there you have it, a major gold discovery several decades before the Custer expedition to the Hills in 1874 (see Post October 7, 2016).  Or, was there even a discovery?  Or, was the entire story a hoax?  Was someone pranking the good people of South Dakota?  I don’t have the slightest idea but carving a message in cursive seems a little farfetched when your keister is being hunted by Native Americans and your gun has been misplaced!  But believers there were/are.  I suppose the most ardent believer was one Frank Thomson who spent something like 14 years of his life following clues and then publishing a book detailing the evidence for the cache (Thompson, 1966).

According to Thomson, he traveled to the eastern U.S. and found several descendants of the miners who stated their long-lost relatives never returned home after departing in 1833 from Independence, Missouri, bound for Santa Fe, New Mexico.  Now, Spearfish, South Dakota, is not even remotely near the Santa Fe Trail so how did the boys end up so far north?   One possibility is that a member of the “dead” group, Indian Crow, was a Native American from the northern plains whom the original members picked up along the way and perhaps he regaled them with stories about gold.  Maybe Indian Crow wanted to go home and decided there was safety in numbers and what better way to entice the white men for northern travel than stories about gold? Who knows?  What is known for certain is that Louis Thoen was a local stone mason, and no one on record has found any of the lost cache of gold. 
The Thoen Stone displayed at the Adams Museum.
So, what was the fate of the Thoen Stone?  Thoen’s children loaned the Stone to the Adams Memorial Hall (nearby Deadwood) in the 1930’s and the Adams Museum acquired it permanently in 1965.  It is a popular display in the Black Hills’ oldest history museum.

Now, that Thoen story is more exciting than me trying to explain the origin of redbeds in the Spearfish Formation.  And, I am off to the area around Chamberlain, South Dakota, where I-90 crosses the Missouri River.
Before the construction of I-90 (and the paved Highway 16).  I would not like to drive on a wet and muddy section of Pierre Shale.
I spent the summer of 1966 working for the South Dakota Geological Survey stationed in Chamberlain.  Our group, led by Survey geologist Richard Bruce, was examining and running drilling tests on the Cretaceous Pierre Shale in preparation for building I-90 and the massive bridge over the Missouri River.  The Pierre was notorious for sliding and slumping and the road engineers were quite concerned.  I still get a little nostalgic when driving by our former study sites and remembering our days spent dropping some sort of a magic wand down the pipe and measuring rate of shale movement.  The Survey was also kind enough to furnish a vehicle for my weekend jaunts to west river and thesis work.

An outcrop of the Pierre Shale.
But, the stay was not all work and we usually ate the evening meal out at Chamberlain’s most “famous” eating establishment—Al’s Oasis. The place is still in business but their long-advertised $.05 coffee seems long gone.  However, the best thing about Al’s, and my stay in Chamberlain, was an introduction to a young lady.  Well, that was a half century ago and we have grown together all these years! 
Many travelers visiting Chamberlain remember the steel bridge crossing the channel of the Missouri River.  With rising waters created by Lake Francis Case the road, SD 16, was extended west (right) via a constructed causeway (1953).  Pillars of an even earlier bridge are in the foreground (1925) and parts of that bridge were used in construction of the 1953 bridge.  Today, most traffic crosses the River on the I-90 bridge just down stream.  In addition, a railroad bridge is even further downstream (1918).
I believe this is a photo of the four span 1925 bridge (each span ~335 feet). The 1953 bridge was built to the left of the 1925 bridge and incorporated spans of the old bridge plus spans of the Wheeler Bridge (shown below).  The new bridge also added twin spans due to increased vehicular traffic (five dual spans).  The 1925 bridge was very narrow but was OK for early vehicles.  The 1953 bridge was then replaced by the I-90 bridge constructed in 1974; however, the 1953 bridge is still in use as I-90 Business. During removal of the 1925 bridge for use in the 1953 bridge a Bailey Pony Truss Pontoon Bridge, a temporary structure, was in use.  What confuses me is---what is the bridge to the right of the 1925 bridge?   Any help??
This is a photo from the South Dakota State Historical Society showing the Wheeler Bridge, 70 miles down stream (~Fairfax, SD) from Chamberlain, crossing the Missouri River.  This bridge was floated upstream to Chamberlain for use in the 1953 bridge.`

Before construction of Lake Francis Case, the Missouri River was a sinuous, mostly shallow, sandbar-laden stream.  These photos from old postcards, dates unknown, shows a docked steamboat (top), well really tied up, at Chamberlain in perhaps the spring runoff season. The lower photo seems to be in late summer as numerous sandbars may be observed. 
Most travelers remember Chamberlain for the bridge crossing the River with the picturesque exposures of cream-colored limestone underlying a black shale.  Actually, the Missouri River was not nearly as wide as today before construction of dams associated with the Pick-Sloan Missouri Basin Project.  This plan, first approved in 1944 and modified in succeeding years, called for construction of six large dams on the Missouri and several smaller dams on tributaries; all were to be managed by the Corps of Engineers.  Some of the earlier proposals seem rather grandiose as some engineers wanted to build a series of lakes with locks and dams in order for barge traffic to extend into the upper reaches of the River.  That proposal was “shot down” and today the Corps only maintains a nine foot (300 feet wide) navigable channel from St. Louis to Sioux City, Iowa.  The latter city is located about 70 miles downstream from the lowest River dam at Yankton, South Dakota. But, as the early steamboat captains knew, the Missouri River is tough to navigate, especially in low water.  The Kansas City public terminal port (Woodsweather) reopened in 2016 after closing in 2007.  A shipping barge finally pulled into Sioux City in 2014 after an 11-year hiatus.  It was not only the tricky navigation that ground the barge traffic to a stop but lawsuits by environmentalists and upstream governments (keep more water in the lakes for recreation), an economic recession, low commodity prices, etc.  Despite the lack of commercial traffic, the Corps labored on, keeping the 9-foot channel clear.  One can only imagine the cost associated with maintenance of the St. Louis to Sioux City 9-foot channel.
Dams and reservoirs associated with the Pick-Sloan Plan located on the Missouri River. The massive Fort Peck Dam in Montana was constructed previous to the implementation of Pick Sloan.  Map Public Domain from Karte:NordNordWest, Lizenz.
The six major dams on the Missouri River are: 1: Gavins Point near Yankton; 2) Fort Randall near Pickstown, South Dakota; 3) Big Bend Dam at Fort Thompson; 4) Oahe Dam at Pierre; 5) Garrison Dam near Garrison, North Dakota; and 6) Canyon Ferry Dam near Helena, Montana.  Each of these dams produce electricity.  At Chamberlain travelers cross the Missouri River that has been modified into Lake Francis Case, backed up by the downstream Fort Randall Dam (River Mile 880). 
Fort Randall Dam backing up waters of lake Francis Case.  Public Domain photo from Corps of Engineers.

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Evidently the first bridge at Chamberlain was a pontoon bridge that was replaced in 1905 by a railroad pile and barge bridge which was converted to steel in 1918.  It was then replaced by the 1925 bridge, shown below with a paddlewheel ferry in 1936.

The railroad (Chicago, Milwaukee, and St. Paul) came to town in the late 1800s but could not construct a bridge to push west until about 1905--this was a pontoon bridge with pilings holding up the approach.  In 1923 a swing bridge was constructed (would have loved to see that) and then was replaced by the 1953 bridge (needed to span the waters of Lake Francis Case).
Photo courtesy of

Lewis and Clark camped on the shoreline across the River from future Chamberlain on September 17, 1804, very near an island that was heavy forested with “red cedar” (Juniper trees) and with abundant native plumbs (from the journal of Clark: Capt. Lewis went on an Island above our Camp, this Island is abt. one mile long, with a Great purpotion ceder timber near the middle of it).  Later this island became known as American Island and was deeded to the City of Chamberlain.  The City developed a “County Club” with golf course, a park with a swimming pool, a race track (type unknown), picnic grounds, camping spots, and athletic fields.  Many Chamberlain residents still resent the loss of American Island when the waters of Lake Francis Case covered the area in the early 1950s.

I had the opportunity to fish around Chamberlain for 30 years.  At times, the water was very high with a strong current.  But in a few drought years the water was so low that several foundations of American Island buildings were peeking just above water level.  Well, my momma didn’t raise no fools so I steered my boat away from the Island.  One afternoon I was sort of halfway snoozing in the warm sun and heard the roar of a larger outboard motor approaching at a high rate of speed---heading right for the shallows of American Island.  That sucker hit one of the foundations head on.  His boat skimmed over the rocks (probably with substantial damage) but the motor’s lower unit broke completely off the shaft.  Valuable, but expensive, lesson learned!

Fort Randall Dam received its name from Fort Randall, the longest serving U.S Army post on the Missouri River.  The Fort was located on the southern side of the dam, on the west side of the Missouri River and was constructed to replace Fort Pierre. After the Dakota War of 1862 (in Minnesota with the U.S. Army battling Dakota and other Natives) white settlers panicked in neighboring Dakota Territory as many of the Minnesota Dakota factions moved west and joined their related brethren, the Lakota, Santee, Yankton, Yanktonai and others.  Then in rode General H.H. Sibley with his Army expedition (~2000) and pushed the Lakota/Dakota west across the Missouri River in the battles of Dead Buffalo Lake, Big Mound, and Stony Lake.  General Alfred Sully’s troops (~1200) were late getting up river (to be in place for a pincer expedition) but still chased the various tribes in battles at Whitestone Hill (1863), Badlands (1864) and Killdeer Mountain (1864). General Sully's base of operations against the Native Americans in 1863 – 1865 was at Fort Randall. During 1870 - 1872 the post was rebuilt at the present site, one-quarter mile from the original location and just downstream. Only the 1875 Post Chapel was spared from the river damming project, the ruins of which were stabilized in 1953 from original plans. Some of the above from (

American Island at Chamberlain had an even earlier non-Native history than Fort Randall.  North American Forts (reference above) noted a St. Louis Missouri Fur Co. post, Fort Recovery, was built on American (Cedar) Island in 1822 and lasted until 1830.  However, other references place the Fort on the shore across the water from the Island (see  In addition, Wishart (1979) placed the location of Fort Recovery near the mouth of the White River, a few miles downstream from Chamberlain.  Then there was White River Post, ~1830, (AKA Brule Post) at the mouth of the White River.  There may have been earlier establishments on American Island (Fort aux C├Ędras and Fort Antoine Brasseaux); however, there is some confusion with these names and other camps/forts further upstream.  At any rate, American Island is “underwater” and perhaps we will never know the answer. 
What we do know is that Fort Lower Brule was built in 1870 near Chamberlain and a month or so later was moved north about 15 miles opposite the mouth of Crow Creek and renamed Fort Hale (1878).  The site is now under water, I think, but would have been on the Crow Creek Reservation now occupied mostly by descendants of Mdewakanton heritage chased out of Minnesota after 1862, and some Yankton and Lower Yanktonai Sioux.  The Officers' Quarters at Fort Hale was sold shortly after closing and ultimately became the Taft Hotel in Chamberlain, a building I distinctly remember. It was moved in 1989 to the vicinity of Exit 263 of I-90, to be used as a museum? but burned in 1990. 
Taft Hotel ca. 1940s.  Original photo by O. Barger, a well known Chamberlain photographer.
Between Rapid City and Chamberlain, I-90 crosses a few nice outcrops of the Tertiary White River Group (really spectacular at the adjacent Badlands National Park) and then drops onto a weathered surface of the Cretaceous Pierre Shale.  Good outcrops do not appear until the traveler begins to approach Chamberlain and descends into the valley of the Missouri River.  One particular segment of the of the Pierre is commonly known as the manganese zone due to the presence of numerous manganese nodules.  In the mid-1940s the U.S. Bureau of Mines experimented with mining and production of the manganese—see Posting June 7, 2011.

Zone of manganese nodules in the Pierre Shale.
The Pierre is well exposed in the River valley and is a striking contrast to the underlying Niobrara Formation—a cream-colored limestone and chalky shale.  On the east side of the River (stay on “old 16” through town) the traveler can easily see evidence of slides and slumps in the Pierre, including condemned houses.
A small remnant of the Pierre Shale, along with some reworked shale, on the Niobrara Formation near Chamberlain.
One of the really interesting aspects of the River at Chamberlain is the tremendous number (thousands) of boulder-size rip rap quarried from the Precambrian Sioux Quartzite (see Posting January29, 2014) brought in (by train) to stabilize the shoreline.  Many of rip rap pieces have marine near-shore features such as ripple marks and cross bedding.
Sedimentary structures on rip rap boulder.  Non-directional ripple marks???
Rip rap boulder of quarried Sioux Quartzite.  Generally the quartzite is an orthoquartzite (as opposed to a cooked metaquartzite) that is composed of quartz sand-size grains tightly cemented by a siliceous cement.  Bedding planes are evident up close examination.  I presume the rip rap was quarried near Sioux Falls.
So, it has been an exciting trip thus far as old memories have surged to the front on my mind.  Now, it is off to the glacial county of eastern South Dakota and Iowa.
Lisenbee, A.L., J.A. Redden, and M.D. Fahrenbach, 2013, Geologic Map of the Spearfish Quadrangle, South Dakota: South Dakota Department of Environment and Natural Resources 7.5 Minute Series Geologic Quadrangle Map 21.

Thomson, F.S., 1966, The Thoen Stone: a saga of the Black Hills: Detroit, Harlo Press.

Wishart, D. J.,1979, The fur trade of the American West: Lincoln, Nebraska, University of Nebraska Press.

William Clark: