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HELL CREEK Formation


              The Hell Creek Formation covers parts of the States of Montana, North Dakota and South Dakota and other areas of the U.S. This formation was formed when the central part of the United States was covered by a huge interior or inland sea called the Western Interior Seaway, the North American Seaway and/or the Cretaceous Seaway, which extended from the Gulf of Mexico upward through the central part of the United States and the north-central part of Canada.

       There was a deposition of fluvial non-marine sediments along the eastern margin of this interior seaway. The formations laid down are primarily composed of sandstone, mudstone and siltstone. Virtually all of the Hell Creek Formation was laid down during the Late Cretaceous. However a small portion, in some areas, of the upper portion, dates to the Paleocene. Further south there is a layer of the same age, which goes by the name, Lance Formation.

       In Canada, in the formation of rock layers which are correlative, we find the Frenchman Formation and the Scollard Formation. All of these these units, stated above, were deposited by ancient rivers that flowed eastward into the the Western Interior Seaway

       Beneath the Hell Creek Formation, there is another rock layer which is called the Fox Hills Formation. In Montana, the overlying layer, above the Hell Creek Formation, is called the Tullock Formation, which is a Paleocene layer. However, in the Dakotas, the formation which lies above the Hell Creek Formation, is called the Ludlow Formation. To the North of the Hell Creek Formation and in other locations where it surfaces, is the Judith River Formation.

       In the Hell Creek Formation, the K/T boundary occurs as a discontinuous thin marker, which however is distinct. The K/T boundary is the boundary between the Cretaceous and the Tertiary epochs, where the huge meteor hit the Earth in the vicinity of the Yucatan Peninsula and the Gulf of Mexico, wiping out the dinosaurs and much of the other life on Earth.



Here are some eART SCANs and photographs of Dinosaur bones, which are on display,
at the PROCTOR MUSEUM of NATURAL SCIENCE in Houston, Texas, U.S.A.

In the four views of the Hadrosaurus metatarsal, a new Texas quarter is used for purposes of showing the size of this relatively small foot bone in this sizeable Cretaceous dinosaur. This bone was found and dug out by Terry Brawner, Pres. of the PMNS. The preparation (restoration from the various pieces) and these eArt Scans were by PMNS Curator Terry Proctor, who was also present when this bone was extracted in Montana.

Hadrosaurus metatarsal
Cretaceous epoch
Hell Creek formation
Wibaux, Montana
View 1
Hadrosaurus metatarsal
Cretaceous epoch
Hell Creek formation
Wibaux, Montana
View 2
Hadrosaurus metatarsal
Cretaceous epoch
Hell Creek formation
Wibaux, Montana
View 3
Hadrosaurus metatarsal
Cretaceous epoch
Hell Creek formation
Wibaux, Montana
View 4
Eroded rock on pedestal
showing how much of the land
level has eroded away over time
Fossil tree stump too large
to recover and bring back.
In fact too heavy to even move
Geologist's hammer shows size
Cretaceous Hadrosaurus
femur in situ with shattered
end and rest buried in matrix.
Notice dark layer just above.
Is this K-T boundary? #68
Cretaceous Hadrosaurus
femur in situ showing the
shattered end of femur
in more detail. #69
Cretaceous Hadrosaurus
femur wrapped on aluminum
foil,in situ, awaiting plaster
and removal from site. #72
Cretaceous Hadrosaurus
femur now removed and transported
from the location, you can now
better see the layer just above
the place where it was removed. #81
Juvenile cottontail rabbit
which hung out where we were
digging out the Hadrosaurus
femur. It would go into a hole
but shortly afterwards, curiosity
got the best of it and out it
came again for a visit. #56
While returning from the Hadrosaurus
dig site, Terry Proctor found this
strange looking caterpillar.
Only after returning to Houston,
did he learn that it is the
caterpillar of a Cecropia Moth,
which is the largest moth on
the North American Continent


In 2006, Terry Proctor, PMNS Curator and Terry Brawner, PMNS President located many interesting fossils and minerals in the Hell Creek Formation, where they were digging. Terry Proctor found a Hadrosaurus chevron (see eArt scan below). This is a bone which was believed by some, at one time, to appear only in male dinosaurs. However, apparently the famous dinosaur Sue had a chevron. A chevron is a bone lying under a given vertebra, but apparently not actually attached to the vertebra. The chevrons may have been part of the support for the large heavy tail, of certain dinosaurs. The chevron is shown below. Terry Proctor also found a Cretaceous crocodile scute, just laying on the surface, broken in two pieces, which have now been restored (a scute is an osteoderm, which is a portion of the hide or body covering of certain animals, such as crocodiles, alligators, caimans, armadillos and glyptodonts).

While excavating a Hadrosaurus femur in the Hell Creek formation, Terry Proctor discovered some carbon residue, covering most of the area under the femur, once he had excavated it. Terry speculates that these carbon deposits could indicate that there had been a great fire, which possibly could have played some part in the death of the Hadrosaurus. However, it is possible that this is some other mineral, perhaps which may have leached out of the Hadrosaurus. In 1994, while Terry was digging dinosaur bones at Como Bluff with famed Paleontologist, Dr. Robert Bakker, Terry found lime balls, in the vicinity of the dinosaur bones. These were fairly round balls, with cores, somewhat like a Sycamore tree seed ball, and with portions radiating out, just like a sycamore tree seed ball. There are some of these at the PMNS at this time.

Below the Hadrosaurus articulate vertebrae and ribs, shown below, Terry found a couple of Upper Cretaceous deciduous leaf fossils, which appeared to be like Sycamore or Maple leaves. These leaves were apparently the actual compressed carbon residue of the leaves, lying as a thin film, on top of very hard sand, which was not quite rock yet. Terry put Butvar glue on the leaf fossils, to preserve the very fragile imprints. These leaves are now displayed at the PMNS, with other fossils and minerals from the Hell Creek formation in Montana.

Hadrosaurus chevron
anterior view
Hell Creek formation
Wibaux County, Montana.
Additional preparation must be done to lengthen the pointed end of the chevron bone
Hadrosaurus articulated ribs and
vertebrae--covered with iron stone
Hell Creek formation
Wibaux County, Montana
Hadrosaurus chevron
posterior view
Hell Creek formation
Wibaux County, Montana
Secret symbol of the
Spiderman Club (joke)
Hematite Fe2O3
These were found in all sizes, shapes and visual appearance, near where dinosaur bones were dug. They are very hard and smooth.


On this same ranch and in the same general vicinity of the dinosaur fossils, Terry Brawner and Terry Proctor found large number of Hematite nodules (Fe3O2), which were sometimes covered with a thin coating of rougher Hematite. In most of these nodules, however, the rougher outer coating has cracked off, leave a very smooth finished nodule inside, which has really weird geometric designs. These nodules are very dark maroon or chocolate brown colored, with a very hard smooth surface after the rougher coating has broken off. Under this outer coating, the inner surface is wrinkled and has geometric designs making the nodules appear like something you would expect to find on some other planet or in outer space. Some have a spider-web looking designs and others look like a porcupine. Some are almost round and others are rectangular with some being very small and other very large. The two Terrys also found sandstone balls which were almost perfectly round. These lay on the surface of sandstone rock which was fairly hard and some of these sandstone balls, were found up on vertical projections of the hard sandstone which were weathered very smooth. In places there were large cap rocks atop sandstone pedestals, where erosion had eroded down all the surrounding rock, leaving the harder cap rocks to protect the softer sandstone pedestals which they protected from erosion.These cap rocks were sometime four or five feet higher than surrounding area. This gives the entire area a spooky surreal appearance (see photos above).

There are several ways which paleontologists can tell dinosaur bone (and other fossilized bone) from other things (such as petrified wood, which can on occasions look much the same). One is by looking at the end of the fossil. Blood vessels and other things in bone, give it a different appearance from wood and natural mineral formation. Another way is by putting your tongue on the item. (Don't cringe--this is true). If your tongue wants to stick to the item (i.e. if it draws the moisture from your tongue, so that your tongue doesn't pull loose immediately), then it is may well be bone, but won't be fossil wood. If your tongue doesn't stick, while it may still be bone, it is probably fossil wood, mineral or something else. If you have a piece of fossil bone, try this. It is handy to have this information when in the field trying to identify a fossil appearing item, to verify if it is bone. Also fossil bone is usually heavy and darker, while more recent bone is lighter weight and lighter color (it hasn't become as mineralized as the older bone has, is usually the reason.