Large Hell Creek Formation Fossils
How many dinosaur ribs can you spot. I count 9 obvious ones in this photo. The camera lens cap is 7.2 cm across. The muddy sediment these are in is rich in bentonite which swells and gets very greasy when wet. It also make seeing bones very difficult as it coats the surface easiy.
Here is a side view of a possible pubis of a theropod from one of my digs.
Notice how robust the shaft is from this side.
Another photo angle of the “pubis” The shaft is much thinner on this end.
This photo shows two squamosal spines from a pachycephalosaur. I am still trying to assemble the rest of this fossil and some minor reconstruction has been necessary to complete this specimen. There is an additional spine to fit to the group. This fossil was found in a microsite directly next to a hadrosaur’s toe. None of the rest of this animal seems to be present at the outcrop.
This picture of my main dining room table shows the general number of projects ongoing at any one time at our place. Finding a site is only a part of the process. Once bones are discovered, they have to be recovered, reconstituted (stabilized), repaired and reassembled. Only then are they suitable for a repository. My tools consist of a wide gamut of digging tools, picks, shovels (of all sizes) chisels, hammers, paint brushes, dental picks, knifes, awls and wheelbarrows. Tarps, canvases, plastic bags, paleobond (superglue), Elmer’s school glue, aluminum foil, plaster and even toilet paper has been handy in the field (in many ways).
As you can see field work is hard, dirty but rewarding. This rib bone just kept going and going 42 inches straight back into the outcrop. You can see the bone has breaks every few inches and in some places is literally powdered. Roots reach deep into the outcrop and tend to follow the porous bone material. Hill side slump also distorts and breaks bone. If you look two feet to the right of my toes, you will see the beginning of the jaw bone pictured below just starting to be exposed. My foot is a foot long.
This is a close up of the ceratopsian horn referenced above. I would love to find the tip. It is there somewhere in the float. This piece also said dig here but it was 20 feet to the right and 30 feet down slope from where the ribs are coming out. Hummm.
Here is a Ceratopsian rib from a pretty close location (less than a mile from my house). These bones rest in a black organic rich shale. There appears to be much more of this animal left in the hillside. The jaw section below also came out from this same spot. There is still some reconstruction work to do on the proximal end due to weathering and the resultant loss of bone material. The ruler is two feet long.
Here is a nice little rib (with T-Rex tooth for scale). These fossils are the first ones from the 2005 spring season. The rib was completely exposed on a block of sandstone that a track hoe knocked off a sand bar deposit in the previous fall. The grid squares are 1 inch on a side.
This jaw section came out with the rib above and a partial horn. It has some weathering effects but is still a fine example. It was found about a mile from my house on the Wyoming side of the border. The image below shows the other side.
This is the reverse side of the ceratopsian jaw. A partial vertebra also came out of this site too. I doubt if there are additional fossils that will be found at this particular site because of the steepness of the hill and the difficulty of extracting or finding additional specimens. The back wall for the excavation is getting higher than I am tall. There is nothing quite like following a 40 inch bone like the rib at the top of this page back into hard shale on a steep hill. At least the diggings fall down the hill. This is big country though and there are many more sites to be found.
Pachycephalosaur skull cap rear view. This fossils came out of the topsoil and fell out of the backhoe bucket as I was first exposing the bench of my first bone bed. It took a vibratool to remove the calcium carbonate surface and currently the specimen is entirely uncovered.
Pachycephalosaurus skull cap top view. Scale is a chapstick container.
Ceratopsian toe bones from my first bone bed. As with other fossils from this site they have a covering of calcium carbonate from the soil. These two toe bones are some of the first stuff to come out of my new bone bed. They are coated with a thin coating of calcium carbonate which can be taken off with some effort of a vibratool and some acetone. They are well preserved under the crust and show original bone surface in some places. I have literally wheelbarrows full of bone pieces from this bed and I just exposed the bench. The top soil derived from the bed rock has yielded most of the specimens so far including the Pachycephalosaurus skull cap above. I have a dozen or so vertebra of various sizes coming out randomly as well (see below). Interestingly I have found only two partial teeth and no claws so far in this deposit. (Both teeth are partial carnivore teeth with NO vegetarian teeth present so far!) I also note a paucity of gar scales and other fossils but there are some turtle shell pieces about. I suspect the smaller stuff was winnowed out of the deposit by the current with only large stuff being left. There is some iron concretionary activity near the top of this bed which seems to be about 2 to 3 feet thick in places.