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Last weekend was to be spent with a Fossil Forum friend touring the formations in my area. Unfortunately the weather forecast showed that a rainout was likely resulting in a change of plans. Connor decided to head south to Kentucky. Being “stood up”, I decided to venture out on my own, in spite of the gloomy forecast, in hopes of creating jealousy with my finds. But based on his recent post showing his wonderful finds down in Kentucky, he was the one who made me jealous. Grudgingly, I will show my findings anyways! These were found in the Elgin Member of the Maquoketa, which is Ordovician. First up are the brachiopods. Then some inarticulate brachiopods. Awhile ago, someone had posted a brachiopod, I believe Strophomena with bumps all over it. Here is another example. Bivalves, sponges, and crinoids are uncommon in this formation. I am not sure if this is a sponge. Your thoughts are appreciated! I am calling the next group of fossils epibionts, though I do not know if they were growing on living or dead animals. Would love to know what these fried eggs are!! Cephalopods of many types are commonly found. The site I looked at is known for trilobites. In fact the lessee of the site and his grandson, who I had the honor of collecting with that day, found some impressive ones. I was probably too busy cleaning up all the non trilobite fossils that they discard to train my eyes on the trilobites!!! In spite of this, I did manage one whole trilobite that is damaged (missing an eye and more) plus many partials. Pygidiums The next pygidium is TINY!!! Only 1/2 cm in width. Can anyone ID it? A few hypostomes were collected. Cephalons are next. Their IDs remain a mystery to me. The rain did hold off until noon, at which time I headed back to Minnesota to collect, where it was dry. @connorp @isotelus
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Early in the summer, an attempt was made to hunt a different Ordovician formation than I normally collect in. It provided me with a learning experience and some new and neat fossils. Having enjoyed my finds so much, a return trip was made 2 weeks ago. Not to the same site but to a more extensive exposure of the Elgin Formation of the Maquoketa close by. The location is in NE Iowa in some beautiful farm country. Even if I found no fossils the view from here made the trip worthwhile. Now for the finds. I am a novice at identifying fossils from this formation and am open to any suggestions or changes to my identifications. Here is a sediment filled cephalopod with Dalmanella on it. Only one was truly part of the find. Which brachiopod belonged to the cephalopod? This one!! Cephalopods of all types and sizes abounded in this formation. This is one cephalopod I would love an ID of. The linear stripes are new to me. Epibionts were common on the brachiopods. Now on to the trilobites. First up is a picture of a u shaped structure just 5 mm long. Is it a hypostome. If so, what trilobite? Many pictures that I hope you enjoyed! Mike
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- ne iowa
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I've been doing some research for a couples weeks about the Isotelus beds located over Fayette county. It's been rather difficult to locate a specific site, so I'm asking if anyone who's been down there has any specifics when trying to locate them. I know of the Turkey river, but I'm four hours away so I just want to make sure I have a clear idea. Thanks, Jonah
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Last Autumn, I took a side trip to Graf, Iowa in search of it's "elusive" cephalopods. Fortunately for me, a large piece of rock had released itself from the overhanging cliff and I proceeded to use my sledge hammer on it until broken into eight 50 lb pieces. This then was loaded into my truck without further exploration as I knew, each chunk contained maybe 50 cephalopods within it. These chunks of matrix were to provide me with a little winter entertainment while the landscape of Minnesota remained white. Two weeks ago I began splitting these boulders, looking for the treasures contained within. At the same time, @Ludwigia posted an image of belemnites , that made me think how similar his finds were to cephalopods of Graf. <img src='http://www.thefossilforum.com/uploads/gallery/album_1563/gallery_2384_1563_281093.jpg' alt='Acrocoelites (Acrocoelites) gracilis (Hehl in Zieten) ?' title='Acrocoelites (Acrocoelites) gracilis (Hehl in Zieten) ?' data-role='theImage'> After complimenting him on his finds, he asked to see my hash plates of Isorthoceras sociale. It is for this reason that I have put a trip report together. This location continues to perplex me a bit. How so many cephalopods over such a long period of time could keep collecting here. From my understanding, Graf, Iowa back in the Ordovician period was a very shallow marine environment where wave action altered how these cephalopod carcasses were deposited. Due to the wave action, many examples of one cephalopod being washed inside the shell of another cephalopod exist. This is very unique!! The septa of these creatures were thin and broke down readily in the surf, leaving space for other cephalopod shells to be deposited within. To show this better, here is a specimen that had all of it's septa dissolved, but the siphuncle still remained!!! Another picture showing the decayed cephalopod with remnants of a siphuncle yet no septa This I understand. But from my perspective, there are several odd factors that defy explanation from my limited knowledge with regard to the cephalopod deposition in Graf. The most prominent cephalopod rich rock is a bit orangish in color, as can be seen above. But there are 2 separate grey/brown zones that the specimens look completely different. First is an area where the cephalopods are flattened like pancakes. If you notice, the gastropods (circled) contain no distortion/ flattening. A mystery to me. The second darker zone contains cephalopods that are very small in comparison to the orange zone. They reach only about10 -20% of the "normal" size of Isorthocerus socialis found in the orange zone. A different species? Or a stress environment where they just didn't grow well? Obviously the matrix changed, so then should their environment have changed. An unknown mystery again for me.
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- cephalopods
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