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Showing results for tags 'minnesota'.
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From the album: Corals of Decorah Minnesota
Platteville formation Lambeophyllum profundum. Outer laver are gone. Uncommon to rare. -
For those of you that hunt rivers and creeks in the Midwest how often do you find horse remains? These three humeri were all found within a 2-mile stretch of a river within about a two year period - along with many other random tarsals, a femur, multiple tibia, and several teeth...
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I am confused about how to id Isotelus species as they all looks alike. I know I rex is out of the range for Ordovician Platteville/Decorah/Galena Formation. #1 is the most complete (minus head) from Galena formation in southern Minnesota. Its also the only Galena one I am showing right now as other still need cleaning. #2 The largest pygidium from Platteville Formation. Not the most complete I have but is pretty wide. #3 I am disappointed with the quality of pics but just showing here. Pygidium of smaller Isotelus species from Platteville with the farthest left the only one from upper Decorah formation but lost most of its mineral covering. #4 Cephalon from Platteville formation (not complete). #5 from platteville is maybe the most complete I have of the small Isotelus species. Maybe even its pygidium is hidden in the carbonate.
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Found on river gravel bar in Sothern Minnesota. I know its a partial tibia - any ideas on species? Sus maybe? Sediments in the area range from cretaceous to holocoen with a good amount of Wisconsin lobe glacial till. Previously we have found bison, mammoth, and ancient horse...
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Id of Ordovician Trilobites of Bumastus and lookalikes of Decorah and Platteville Formation
Tetradium posted a topic in Fossil ID
#1 is one of the only complete trilobite I had not identify genus yet. Rolled up and in a tough to clean rock. Upper Decorah Formation (formerly Cummingham Formation). Cant see any eyes yet. #2 I had picked for size - Platteville Formation. Also because they have those lines you can see more clearly on the NE specimen. #3 is the tiniest of the Decorah formation group. #4 is the largest of the Decorah group. I had double and triple checked to see if it is a brachiopod - nope. #5 is the tiniest of the platteville group. Compare to #3 its much more strongly oval shaped.
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From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
not identified yet. Two very similar genus. -
From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
Unidentified orthid for now. Strongly resembles Dalmanella sculpta but have sharp edges. -
From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
Pionodema conradi. I knew I had some tiny orthid brachiopod from Middle Platteville Formation but after checking book and this website: https://2dgf.dk/xpdf/bull26-01-02-115-132.pdf Kind of weird. I think Hesperorthis concava was invalid - too similar and two very close look alike can't compete with each other. One other brachiopod mention on the list Campylorthis deflecta look too much like Strophomena species despite a website saying genus name is valid. -
From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
Zygospira sp. Apparently there are a mystery with this genus when it comes to Twin Cities. I first noticed it only from Middle Platteville Formation - 100% nonexistent from upper Platteville Formation. Much more finer costae compare to Rostricellula minnesotensis and generally smaller. Belongs in Spiriferid family despite it strong resemble to Rhyconellid family. Then after a very long absent either the same species or a very similar species popped up again in upper Decorah formation and became very abundant. I suspects the reason for this seemly weird pattern is they may be much more specialized into the type of sediments that laid on the ocean floor. The middle platteville had layers of high carbonate shale mixed in, which does not exists in upper and lower Platteville formation. Then upper Decorah formation had a harder type of shale - middle and lower Decorah formation have shale that breaks into pieces very easily. Plus from my experiences with modern Florida gastropods there are two endemic species of gastropods that had very narrow ranges. One I don't have specimens of is Sanbriel Island turret snail which is endemic to southwest mainland Florida. Not found anywhere else. The other snail species, Shiny Atlantic auger, Hastula hastata is only found generally around Jupiter Island on Atlantic side. At first it may seem like the two snail species have nothing in common but I find it interesting that they occurs in a small zone in between the carbonate sediments of far southern Florida to the keys and the sandy rubble to the north. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
Another interesting thing about Upper Decorah Formation is numerous of unidentified Zygospira species along with orthids of different sizes. For some unknown reasons Zygospira species are largely missing from lower to middle Decorah Formation even though they're abundant in Middle Platteville as well too in Twin Cities. -
From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
The first three pictures are Ectenaspis beckeri. I usually don't like to work on trilobites much because of their fragility and their 3d structures plus I don't know what tools that's available to use with it. How I came to the conclusions - it have continuous solid structures which means (edited Thorax) are missing from this specimen. The tip is missing and maybe parts of the head as well. It have a unusually elongated head and its (edited genal) spine appear to be curved. One theory I have is it is upside down. From Decorah formation. Don't know if its rare or uncommon as bottom half looks similar to others from the same family. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
Prasopora conoidea with unidentified bryozoan. You can also see rust stains. Rust stain can be very prevailing in some layers or spots on rocks. Mainly because glacial deposits tend to be very iron rich from Norrthern Minnesota and then they get dissolved in groundwater and redeposit on the fossil shell hash because they're much harder for water to pass through. Another thing to know: Prasopora strongly prefers muddy sediments and thus wont appear or rarely in carbonate rich environment. . -
From the album: Platteville to Decorah formation Ordovician Twin Cities
Some orthid brachiopods, mainly Cincinnetina and Dinorthis along with several lookalikes tend to be found only in Upper Decorah Formation. Upper Decorah tend to overlaps with Galena Formation and Richmondian formation. That's why you can find some of the same orthid brachiopod species from Minnesota to Ohio to Kentucky. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
First Vinlandostrophia brachiopod find of the year! I will have to compare it to the other two species later. Hash is much more fragmentary - I call it bryozoan hash. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
Larger picture of the same trilobite. Just to show an example of upper Decorah twin cities hash plates. Certain crinoid species are very strongly represent compare to middle and lower Decorah Formation. The largest crinoid species is often in single pieces or sizable stem pieces but head and suction portion are unusually absent. In Middle and Lower Decorah formation, the density of crinoid fossils tend to be lower. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
One of the fossil found yesterday in upper Decorah. I think it is Basiliella barrandi as very few Decorah formation trilobites gets that big and have sizable genal spines. -
From the album: Platteville to Decorah formation Ordovician Twin Cities
Yesterday I went on first fossiling trip of the year. Its one of a pretty small timeframe in which I am able to accessible certain sites as thaws are happening but marshlands are frozen. Two years in row found a sizable agate in very different locations - last year was on a sandy road recently constructed up north Minnesota. This agate (right side) is hardly chipped. The left side is typical twin cities glacial deposited japser - certain sites far north Minnesota produces superior quality jaspers by compare. This one is much more smooth on one side and more redder than usual -
From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
Another angle. -
From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
Turn out that is where the missing thorax is! So tightly coiled than I thought. -
From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
This one specimen is a typical head - it is much more pointed. Then I accidently chopped a piece off and got a surprise. -
From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
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From the album: Trilobites of Minnesota Decorah/Platteville/Galena Formation
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From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
?Oepikina minnesotensis. I'm not 100% sure yet. Oepikina tend to have very fine costae and those specimens are literally loaded with costae making them darker. There's two in the leftmost rock specimens along with a Strophomena. The annoying thing is its hard to see hinge line for a positive id. Among the most inflated brachiopod I have seen from Decorah formation, only inarticulate brachiopods are this inflated. -
From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
Sowerbyella minnesotensis. Upper Decorah formation, all of Galena Formation. Tend to be characterizing into identification of Upper Decorah formation (only exposed in Lilydale Regional Park and southern Minnesota). Other locations in Twin Cities tend to be lower (maybe middle) Decorah formation. Very abundant, can make up a big section of some shell hash. The one specimen in the middle is the largest and complete that I had found so far. -
From the album: Brachiopods of Platteville/Decorah Twin Cities Minnesota
?Cincinnetina minnesotensis. Middle Platteville Formation, rare. I hadn't found any Hesperorthis in middle Platteville yet and there's lack of information on Platteville orthid brachiopods as I have one to two other species from middle platteville but they're tiny and difficult for me to photograph at current. The big brachiopod in NE rock is Oepikina inquassa - they have very fine costae and may appear to be darker because of it.
