Using the book "Rockhounding Montana" by Montana Hodges & Robert Feldman as a guide I headed to Makoshika State park in Glendive. I stayed in their campground for a week ($10/night) before moving to Glendive City Park (free) for another. I moved to the city park to be close to the Yellowstone river. It was a fun diversion to occasionally wade the river for agate instead of hiking the hot sagebrush and shale of Cedar creek.
Every day I would drive south of Glendive to a parking lot for the OHV area. This was the beginning of a washboard gravel road and I would unload the 4-wheeler and use it to get to Cedar creek and beyond. To make sure I hunted a different part of the Pierre shale every day, I made a grid on the BLM map for the area. I quickly determined where the good concretions were just by the busted and weathered pieces lying around. This area gets a lot of action by rockhounds and all the exposed concretions have been hammered. Using the many oil and gas pumping station roads in this area and hiking up in to the gray-black shale was the only way to find that just exposed nodule.
In the 2 weeks I spent there, I found four barite containing septarians. I spent a lot of time and effort and covered miles of sagebrush and cedars to find so little. If I had to find another one today I probably would fail. Mother Nature needs some time to expose another treasure.
If this inspires you to go here, and finding a barite containing septarian seems futile, head up Cedar Creek for a few miles and the pretty yellow and gray agatized wood starts showing up in the gravels and bars in the creek. A nice petrified wood specimen can easily be found. You must get up Cedar Creek a good mile away from the main road. The wood has all been picked up where little effort is required. Well... except for one huge root ball that I could barely roll. This big specimen is hanging out in the bed of Cedar Creek just up from the road. It will be there for a long long time. This wood is legal to collect following BLM rules of 25 pounds plus one piece a day, not exceeding 250 pounds a year.
The Pierre shale is located on an anticline so it's not consistent in relation to height. The key to finding the barite is the large smooth skined concretions containing pelecypods (sea shells). When you see these, you are too high. The barite containing septarians are in the strata just below those large solid nodules. There are many busted calcite containing septarians laying around. Find where these busted pieces are and look closely, under trees, and in that level of strata to find that just exposed nodule. It is not easy, so if you only have a few hours to hunt, get up into the shale quickly and just enjoy the busted nodules left by previous rockhounds. They are full of fossils.
The baculite fossils are found down by the creek. Search the small ravines feeding into Cedar Creek, and the dense cedars growing on the small hills near the creek banks. The good collecting area is within the first two miles of the creek heading east (upstream) from the road. I found one small nodule with baculites sticking out both ends. There is/was a lot of float laying around, but it is too close to the road for any easy finds.
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The hills containing the septarians... looking north northwest. The banks of Cedar creek are showing in the center of the photograph. I am on the wrong side of the creek. I found only baculite float, no septarians, on the south side of the creek. Get up into those hills, that is where the shale with the septarians is. Don't climb to the very top of the hills, stay lower, in the shale, just below those big smooth pelecypod nodules.
Petrified wood of Cedar Creek.
Baculite float. I tried to match up the pieces. I once thought this was dinosaur bone until I came to my senses. No dini bone in the Pierre shale. This float is found down low in the shale near the creek.
Just exposed nodule. Any exposed concretion is broken up by previous rock hounds. To find a good one it must have just been exposed by Mother Nature.
This nodule is very big.
This is the first Barite containing septarian I found.
Close up of barite cluster. The space between the calcite coated walls is very small. The barite cluster is attached to both walls and sadly, gets broken when exposed.
Barite crystals, with no room to grow between the calcite coated walls.
Three types of concretions found in the Pierre shale. The one on the left is always smaller than the other two (soccer ball) and has noticeable small ammonites and other fossils on the shell and is very solid. It Contains many fossil shells including ammonites, gastropods, nautiloids, and echinoids. The middle one is the barite containing type. It is usually basketball sized with small bumps and fossils on the outside shell. The one on the right is the type containing numerous pelecypod shells. Most are much bigger than the one pictured. They are almost solid pelecypods but the outside skin on these pumpkin sized nodules is very smooth.
Iridescent ammonite with barite crystals inside the shell. Sometimes the barite crystals were amber on the bottom and clear on the tips (like these pictured), other times just the opposite.
Ammonite weathered out of a large concretion. The large smooth pelecypod nodule would always contain one or two hand sized ammonite fossils. They were not worth the effort it takes to bust up this granite hard nodule though.
This nodule was just exposed. The cracks in the shell tell me it has some hollow and is not solid. The size was wrong for the barite and calcite type... too small. Still... a great find, very exciting.. get camera!
It contains a nice ammonite.
Nice ammonite specimen on matrix.
Nice potential barite containing specimen. Notice the small crack which indicates it is a septarian (contains spaces inside for crystals). I saved this one to be cut with a saw.
Pretty small ammonite with iridescence.
Barite cluster that had a little more space to grow.
Pretty three-inch barite crystal against calcite.
A barite crystal cluster that crystallized the only way it could. Very strange crystallization forced by its environment.
Pretty clear barite crystals with bourbon colored points. These crystals had no room to grow, so are severely flattened.
Five inch barite cluster pointing to a crystal spray in this weathered septarian.
Barite cluster in the same septarian as the previous photograph.
What looks like a piece of wood in this fossilized nodule.
Every kind of fossil shell imaginable in this Pierre shale nodule.
Barite crystals pressed against a calcite coated ammonite and ammonite casts. Notice the big barite crystal with the small ammonite cast (in the middle of the left one of the two big crystals). This cast was from an ammonite in the other half of this septarian.
Gray gemmy calcite coated ammonites with amber barite crystals. The small white spots on the ammonites are clear barite clusters and singles. This septarian really sparkles in the sunlight from the gemmy calcite coating.
This particular specimen, featured in the last three photographs, had no cracks and so was not weathered. I cant imagine a finer rock specimen comprising both mineral crystal and fossil. Just a great rock.