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Went to my property the other day to pick up our camping trailer and couldn't help but go through a couple more boxes in my fossil shed. Found these in a tote with a bunch of Scotia Bluff material. Not sure why they were in that box but made for a nice surprize. Here's the thing, I can not remember the name of these fish, the formation or the age. Nothin. All I know is that I got them from a chinese dealer long ago in Tucson. Any help is appreciated. thank you and I got more in the garage. RB

Hi everyone, After the thunderstorm yesterday, me and some friends drove up to the Ponderosa area of Mazon creek park to look for fossils. It was our first time, and we didn't know the specifics of what to look for, but we spent three hours walking the whole perimeter of the lake, braving the aggressive swarms of biting insects. Can anyone here tell me if any of the rocks we found are the right ones to possibly contain fossils? Attached is a picture of all the rocks, and an album with closeup pictures. https://photos.app.goo.gl/XoCZQJwgWU7dbcoS7 Thanks a lot!!!

This is a statement that I often make to myself throughout the Summer and the vast majority of the time I decide to stay home. This was not the case in decades past and it is not because I am older and slowing down, which is definitely not the case, the main culprit is vegetation. Today I had the idea of going to the Pit and taking pictures of the area so new collectors can see areas that they collect at and also see the conditions that they will face in the summertime. I usually go to the Pit at the beginning of the fossil collecting season (March 1st), this is your best chance to find concretions since there is no foliage. Now I also am not saying that there are no fossils to be found in the summertime, I found some today and I was not really looking, it is just that much more difficult and when you add the ticks and mosquito's into the mix, it makes for a real fun day.- NOT. So this morning I left at about 8:00 am for the 45 mile drive to Pit 11, I brought a small backpack and a hammer along with my mountain bike, I was really glad that I brought it. I road up and down hills, road through mud and water and across flat lands with 3+ foot vegetation- after 4 hours I decided to leave. This Post is PICTURE HEAVY and will take SEVERAL POSTS to complete, so bear with me- I will include screen shots of aerial views as well as a couple pictures from about 20 years ago to show how things have changed. This post should also help the new comer get acquainted with the area the so they gain hopefully have better success when collecting. If others have pictures or other things that they will like to add, please feel free to do that. The first area that I stopped is an place that we use to call "Inside the cooling lakes". Years ago before they made this all access entrance, we had to enter on the other side of the cooling lakes at a location called "Fossil Gate". This was an area that was only opened on Saturdays and Sundays and it was manned by a guard from the Nuclear Power Plant. Cars would line up and when the guard opened the gate, you had to show your collecting pass and he would double check it against cards that they had with our signature. Once everything was cleared, you were free to drive in and find your area to collect. There were times when only me and my son were out collecting and the guard would wait in the shack until 4 pm when we left, it was pretty sweet. Mazonia / Braidwood State Fish and Wildlife Area This is an aerial shot of where you turn in for the Mazonia area that allows access into the cooling lakes. The island that you see below is Turino Hill and it is about the only place that is still free of vegetation on the sides of the hill. I collected this area a few times with a friend that had a boat, there are fossils to be found there. The other shot shows the parking lot where you will leave your car. After you park and you are getting ready to go collect, if you are facing the lake, you want to go down the road to your right. I have never found anything on the road to the left, except fishermen. Here is an aerial shot that shows the other islands that you can collect on if you have a boat. Here are a pictures of Turino Hill- On top of the hill there is a flag. Here is a picture of Turino Hill and the Nuclear Reactors to the right. A close up- Here is the road to the right, you can go past the chain blocking the path, it is there so no vehicles drive down the road. Again, before they made this entrance we had access to that road, only from farther down it- it saved a lot of walking. You can check for concretions along the shore, but at this time of the year it gets really rough to get to the shore as you continue down the road, as shown below. I crossed the chain and continued down the road on my bike for about 15 minutes until I arrived at an area that I use to collect at in the Summertime- it has really changed. Below are some older pictures of how it use to look. As you can see from the pictures above, there were plenty of places to collect concretions that were weathering out of the sides of the spoil piles. Here is an aerial shot of where this collecting area is. I will show pictures of how this area looks now in the NEXT POST.

Hello everyone, I am slowly trying to get the things in my collection more organized and here I have a piece of what was sold to me as coprolite from Madagascar, I was wondering if we can certainly call this a coprolite and not just a concretion, And if so what animal could it have come from or what the age is as that was not given along with the piece. Ruler is in inches. Thank you everyone.

I've been planning a fossil hunting outing with my son for the next week or two (weather permitting), and yesterday my wife kindly suggested that I scout out the site before I take our 8 year old on a fossil hunting trip deep into the woods where no cell phones reach. So, when today turned out to be mostly sunny and pleasant, I hopped in the car and headed to a location that sounded promising on old geologic maps/reports (by Rau in the 1950s-60s, to be precise). And it turns out that (as always) my wife was correct -- the logging company who owns the land has apparently erected a gate blocking vehicle access to the road I was planning to use to get to the site, which was not on any topo maps including the relatively recent FS Topo that encompasses this area. Their sign said it was fine to hike in as long as I didn't remove any "special forestry products." Pretty sure fossils don't qualify! I was originally planning to start with what Rau called "Tl-3," one of the lower (geologically) members of the formation, but in light of having to hike instead of drive, I opted for a closer member, Tl-5. After a short walk on the road, I struck out for the stream I was targeting through the woods. This is the part where I'm pretty sure my son would not be capable of pushing through the underbrush on steep and soggy stream banks, so I'll have to find another site for next time, preferably within easy walking distance of a logging road I'm allowed to drive on. When I reached the first exposure of the formation, I could see clear evidence that I wasn't the first person to visit this site (no surprise there), in the form of piles of debris at the base of the bank and a few clear empty spherical gaps in the outcrop. But, I had no trouble finding many small concretions (shells or nothing, I assume?), one large misshapen one (maybe not even a proper concretion?), and one nice looking one that I assume contains a crab, so I suspect no one had been there since the most recent tree-falls and rockslides. I scrambled up, down and along the bank for about 45 minutes, collecting any concretions or fossils I saw either exposed or lose, but did not attempt to expose anything new (maybe next time!). I found a very nice piece of fossilized wood in the debris pile, too, which I can only assume previous visitors to the site mistook for ordinary wood. I am tired and dirty and need to do some household chores, so I will save the whacking of concretions for another day, and probably not do the (likely) crab at all until I have the proper tools to prepare it right. First I'll attach the complete collection of finds, then add a few closeups of the wood in the thread below.

The Advanced Dinosaur Egg Guide Please share this with those who have egg questions. When possible, technical terms were avoided or defined. Every effort has been made to ensure accuracy, but it is always important to do your own research. This guide is merely a snapshot of information taken from many scientific publications. I am not an expert on eggs, rather I just love sharing what little I have learned over the years, what science has learned over the years. For an overview on how to spot a fossilized dinosaur egg and the sizes of eggs, see the basic guide: Somewhat outdated yet still a good overview of dinosaur reproduction and eggs, with a focus on Mongolia: What is so special about eggs? The amniotic egg is one of the most significant evolutionary adaptations as it allowed vertebrate life to permanently exist on land. Long before the dinosaurs and their modern descendants including the chicken, the egg came first. In fact, the better question to ask is “Which came first? The lizard or the egg?” Before the amniotic egg, amphibians and some fish were the only vertebrates able to even venture on land and only for rather short periods of time. A great deal of information has come from studying eggs. What we have learned is summarized as: From University of California Museum of Paleontology Egg Anatomy: Using the best known modern avian dinosaur, the chicken--scientifically Gallus gallus, let us go over the different parts of an egg: “(A) The generalized anatomy of an egg. (B) The chicken eggshell comprises three crystalline layers, including the mammillary layer, prismatic layer, and external layer. The cuticle layer overlying the calcareous eggshell is further divided to two layers, including a HAp inner layer and a proteinaceous outer layer. The shell membrane, namely membrane testacea, is also characterized by two layers. (C) SEM image of the cuticle on the surface of the Gallus eggshell, showing a patchy and cracked pattern. (D) SEM image of the radial section of the Gallus eggshell. The white arrow indicates the cuticle layer that lies on the calcitic eggshell.” From Yang et al. 2018 Fig. 1 Those were technical terms, so how about we simplify. The chicken egg has three distinct shell layers mainly made of calcite, then a soft membrane on the inside of that. What is known as egg whites are the albumen which surrounds the yellow yolk located near the center. The embryo develops within the albumen and is fed with nutrients stored in the yolk. The surface of eggshell is full of openings, tiny pores, and these allow for gas to pass through the shell. A developing embryo needs to breathe just like any animal. Additional information: http://www.ucmp.berkeley.edu/science/eggshell/eggshell1.php How to spot a fake egg: First, the best way to avoid fake eggs is to go and collect them yourself. Always make sure to follow the laws and have permission to collect. In the United States, typically a good way to follow the law is through collection on private land with expressed permission from the landowner. Views of paleontologists do range on private ownership of fossils with many not condoning or endorsing. I personally have little issue with it since amateur collectors have made countless important finds while prospecting for their personal collection. If you are going to buy, do everything possible to ensure the egg or any fossil was legally collected. Often with fake eggs everything seems too perfect. Eggs are delicate and easily crushed or damaged so if there are no signs of any damage or natural alterations be very wary. If the surface has ridges, check to see those ridges continue across a crack or break of the shell. Many fake eggs are mosaics made up of real eggshell fragments assembled together in an egg shape. These mosaics tend to not have the eggshell match on opposite sides of a crack. If you would like more information beyond what is provided or have an unanswered question, feel free to start a thread. If after reading, you want to purchase an egg then please ask the seller for the best pictures they can provide of that egg with something to show scale such as a ruler and start a thread. There are many on the forum who are happy help determine if an egg is in fact real. Just please, whether collecting or buying, make sure you know the laws and follow them. A few good threads on real vs fake eggs: http://www.thefossilforum.com/index.php?/topic/69391-examples-of-commonly-faked-dino-eggs/ http://www.thefossilforum.com/index.php?/topic/83533-red-flag-on-hadrosaur-egg/ http://www.thefossilforum.com/index.php?/topic/71462-beware-of-hadrosaur-eggs/ http://www.thefossilforum.com/index.php?/topic/79465-this-is-how-realistic-a-fakereplica-oviraptor-egg-looks/ How are eggshell and eggs classified? Many people try to name an egg to a specific dinosaur, usually incorrectly. With embryonic remains, however, an egg can be scientifically linked to a particular dinosaur (explained in the next section). Another accepted way for eggs to be linked is through a pregnant female, there are examples of females which died while carry eggs internally. Adults on top of a clutch can be used however only with caution. Eggs are given their own naming scheme just as animals have theirs. In normal taxonomy, we have species, genus, and family whereas eggs have an oospecies, oogenus, and oofamily. The term used for egg taxonomy is parataxonomy. Parataxonomy is used in place of traditional taxonomy when an actual animal or plant cannot be linked, for example--from a lack of data. In the case of Troodon formosus, its eggs are the oofamily Prismatoolithidae, oogenus Prismatoolithus, and oospecies levis. Parataxonomy is the same system used for trace fossils, such as footprints which are normally not linked to the dinosaur who made them. What is inside a fossilized egg? Is there a yolk? What about bones? Very rarely are embryonic bones found, typically eggs have been filled in with sediments. These then lithify (become rock) and so the inside of nearly all fossil eggs is rock that is similar, if not identical, to the surrounding rock. Eggshell is brittle by its nature and so often cracks, these cracks allow whatever sediments are surrounding to fill in the egg and, depending on how recent it was laid to said crack, allow the amniotic sac and other fluids to drain out. Here is a CT scan of some eggs I am working on. You can see how the surrounding rock is very similar to the inside of the eggs. In addition to looking for embryonic material, the scan gives us information on the infill, the true shape of the eggs, and reveals anything which could otherwise not be seen within them. Sometimes insects can be found near an egg, for example. Embryonic bones from the oviraptor Citipati, this embryo is curled within the egg. From Wikimedia Commons Importance of Embryonic bones: https://youtu.be/cubdagTiRHE?t=48 Embryonic remains are vital for an actual animal ID, so any chance of them being present must be investigated. If you have any tiny bones which can be seen inside an egg or directly near it, I would strongly encourage you to take the specimen to your nearest paleontology related museum or university. If it does have embryonic remains in or near, then the specimen is invaluable to science. The presence of those tiny remains allows for the next question to be asked. Do we know who laid this egg? Which particular dinosaur? Most likely no, there are some wonderful exceptions though. Several ootaxa (eggshell type) are known to the dinosaur genus or family they were laid by. Here are some examples of eggs and eggshell which were linked scientifically to a particular dinosaur from embryonic remains. Dinosaur or family and its known egg type, oogenus or oofamily. This list is not comprehensive as new discoveries and revisions are made every year. Allosaurus sp. known to Preprismatoolithus coloradensis. (This is debated) Beibeilong (Oviraptor) known to Elongatoolithidae. Citipati (Oviraptor) known to Elongatoolithidae. (See the picture above) Gobipipus (Avian) known to Gobioolithus minor. Heyuannia (Oviraptor) known to Elongatoolithidae. Hypacrosaurus (Hadrosaur) known to Spheroolithus oosp. Lourinhanosaurus (Theropod) known to cf. Preprismatoolithus. Maiasaura (Hadrosaur) known to Spheroolithus oosp. Oviraptorid known to Elongatoolithidae. Therizinosauroid (med to large theropod) known to Dendroolithidae. Titanosaur (Sauropod) known to Megaloolithus patagonicus. Troodon (small Theropod) known to Prismatoolithus levis. Generally, be wary of any claim that an egg was laid by a certain dinosaur! Additional information: http://www.ucmp.berkeley.edu/science/eggshell/eggshell3.php What groups of dinosaurs do we have eggs for? The vast majority of eggs are from non-avian theropods. This group includes dromaeosaurs (like Velociraptor), allosaurs, and tyrannosaurs. We also have eggs from Mesozoic aves (birds), hadrosaurs (duck-billed dinosaurs) and sauropods (long-necks). It is worth noting when we say that the majority of eggs are therapod we mean it. Around 61% of the eggs found globally are therapod and between 41-64% are maniraptorans (birds and their closest non-avian dinosaur relatives). For the others the numbers are much smaller: 7% are sauropods, 13% are ornithischians (hadrosaurs and relatives) with 19% still unknown and that is no yolk. Here is an example of a clutch from an oviraptor, elongated eggs are typical of many theropods: Pic from The Zuhl Museum On the non-dinosaur side of things, we also have eggs from turtles, crocodiles, lizards, and pterosaurs (flying reptiles). There are several groups of dinosaurs who have no egg representation in the fossil record yet. Despite many people trying to find them, there are still no ceratopsian (horned dinosaur) eggs. There are no ankylosaur (armored dinosaur) or stegosaur (spiked/plated dinosaur) eggs as of yet either. This could simply be due to bias in the fossil record but there also could be other factors. Perhaps, it is a case like the ichthyosaur (marine reptile), which gave live birth, unlike most reptiles that lay eggs. Most of us are familiar with the platypus in the mammalian world, which lay eggs despite being a mammal. Maybe some dinosaurs did not actually lay eggs. Now that would be an eggciting discovery! Below one can see how similar clutches are for two very different types of hadrosaurs. The above is a rather typical egg clutch for a hadrosaur with spherical shaped eggs. Some of these eggs had embryonic remains which allowed them to be identified to a dinosaur. In this case they were narrowed down to within the lambeosaurinae subfamily but sadly could not be narrowed further. Pic from Museum of the Rockies Clutch of another hadrosaur, the good mother Maiasaura. Again, the eggs are spherical and embryonic remains allowed the eggs to be linked with Maiasaura. Pic from Museum of the Rockies The great identification mistake: Now that it is abundantly clear the only way to link a dinosaur and an egg is with embryonic bone. Why is that? Surely there must be other ways to ID who an egg is from. Well, let me share the story of poor Oviraptor, who was wrongly accused of stealing eggs. When the first Oviraptor was discovered, the skeleton was not alone. Underneath it was a clutch of eggs. At the time there were no embryonic remains in these eggs, so it was assumed that the strange looking animal was, in fact, stealing the eggs from Protoceratops, hence the name oviraptor meaning “egg thief.” Later, not far from the original site, another nest was found, this time with an almost perfectly preserved embryo. The embryo was clearly of that of an Oviraptor to be eggs-act. So, with both discoveries, paleontologists determined that Oviraptor was actually a brooding dinosaur much like birds today. This story is an eggcellent example of science improving upon itself and the need to be careful with assumptions. Paleontology is an ever-changing field, which constantly works to improve our understanding of the prior natural world. A common incorrect identification nowadays is that of “Tarbosaurus eggs.” Tarbosaurus is very similar to Tyrannosaurus rex, however, it lived in Asia. Among the largest of eggs ever found, were two measuring 11 cm (4.3 in) wide and an amazing 60 cm (24 in) long. The elongated shape meant they were probably from a large theropod and so were thought to be from Tarbosaurus. Scientifically these eggs are the oogenus macroelongatoolithus. Based on detailed analysis, these eggs most likely are from a large oviraptor and not Tarbosaurus. Alright, so then how are eggs differentiated and how without embryonic bones would an egg likely be from an oviraptor? How are eggs distinguished from each other? We went over how to link a dinosaur to an egg, what about one egg to another or finding differences between eggs? Well, there are a few different ways, one is the surface of eggshell. Many eggs have different textures but surface texture can be eroded or altered so cannot be used alone. Thickness and porosity of eggshell can be measured and provide solid data points for comparisons. Two of the best techniques for examining eggshell are with the use of SEM and thin sections. A scanning electron microscope (SEM) is a very powerful microscope, which can view objects in eggstreme detail. Petrographic thin sections are tiny slices of a rock so thin that light can actually pass through it. Both SEM and thin sections allow for the tiny details of eggshell to be visible, meaning unique traits, variations, and similarities can all be seen. Below are two types of eggshell, how many differences can you spot? A thin section of hadrosaur eggshell, there is only a single continuous layer. Pic from University of Calgary A thin section of oviraptor eggshell, there are two distinct layers with the arrow showing the point where both meet. Pic from University of Calgary On thick eggshell, the cross-section view can often show many details otherwise too small to see. Below is Faveoolithus eggshell, which is large enough to show the internal structure of the shell itself. Pic from Montana State University, taken by P. Germano Naming: Dinosaur eggs, much like actual dinosaurs, are named following a convention with information in the name, and normally an honor to an individual or location where it was discovered. As already covered, naming uses a system of parataxonomy and with eggs, this is called ootaxonomy. Using the method covered above, similarities and differences of eggshell can be identified. Based on these similarities and differences, eggs can be grouped. Some of these groups are associated with a type of dinosaur. As already covered, from embryonic remains or other methods an animal can be linked and associated to its eggs. Sometimes eggs can be grouped based on similarities yet there are no ways to associate them with a dinosaur, so these are listed as unknown. An egg group being associated to a type of dinosaur does not mean all eggs within the group are exclusive to that single type of dinosaur. Some eggs were named prior to the naming convention being established or do not fit any of the known groups, as such these have a truly unique name. That said, most eggs fit one of the following: Name- dinosaurs associated Sphero- Hadrosaurs Ovalo- Unknown Faveo- Unknown (Could be sauropods) Megalo- Titanosaurs Dictyo- theropods Dendro- Therizinosaurs Elongato- Oviraptors Prismato- Troodontids Egg and dinosaur associations, from top to bottom, Elongato- with Oviraptors, Sphero- with Hadrosaurs, Prismato- with Troodontids, Dictyo- and similar eggs from unknown theropods. Pic from the Royal Tyrrell Museum What time periods do we have eggs from? Nearly every egg from the Mesozoic is from within the Late Cretaceous. One study found of 238 eggs examined, 225 were from the Late Cretaceous, 10 from the Early Cretaceous, 2 from during the Late Jurassic and a single egg from the early Jurassic. Since then more eggs have been found, yet the trend holds. A likely explanation for such massive bias would be the Late Cretaceous is more recent so eggs from then are more likely to be preserved and undergo less alteration. Did an egg hatch? The hatching question is a difficult one to answer scientifically with most egg specimens, of course, a nearly complete egg is likely unhatched. Much of the strength in eggs comes from their shape and this means once there is an opening in the shell that strength is lost. There are many ways for an egg to break, one of which is the baby breaking out, but many of the broken eggs we find may have yielded no baby. The term unhatched and failed are often used interchangeably but the term failed is preferred as “unhatched” which implies the egg was fertilized and had a real chance. It is possible and likely probable that no fertilization was the cause for many eggs to not hatch. An overview of the different ways an egg can be filled. From Mueller-Towe et al. (2002) Nest? For as rare as eggs are, finding an egg clutch within a sedimentary structure is many times rarer. There have been several sedimentary structures found around egg clutches, which were interpreted as nests. One of the most interesting of these is a “U” shaped structure which looks similar to a horseshoe, see the picture below. In the center of this “U” shaped structure was a clutch of Troodon eggs. It is possible many nests were constructed like modern bird nests, with sticks, straw, leaves and other such material. This material in nest building, unfortunately, means they would most likely not preserve. Possible nest structure for Troodon, tape measure equals 1m (39in) and the white plaster jacket is covering a clutch of Troodon eggs. Modified from Varricchio et al. 1997 How can we tell what happened to an egg and the nest? By studying modern nests, it was found eggshell fragments tend not to travel very far while remaining in large concentrations. This means when a large grouping of eggshell fragments are found, it is unlikely they have moved much. Modern eggshell fragments can be found in ratios of concave up vs concave down based on what happened to the nest. For example, if a nest had a predator come and eat eggs, the eggshell would be concave up vs down in a ratio of about 70:30, sometimes 65:35. Obviously, if the eggshell fragments are moved then ratios will not work, but again, where high concentrations of eggshell are found, there was little to no movement. The ratio technique is still in the early stages of being applied to nest from the Mesozoic so in time there may be more information. The Emu eggshell above is concave-up. Pic by P. Germano The Emu eggshell below is concave down. Pic by P. Germano In both pictures, different layers of the eggshell can be seen and such layering indicates the eggshell is from a theropod, in this particular case, an avian. Where in the world are dinosaur eggs found? Eggs are extremely rare and there are only a select number of places where they have been found so far. Eggshell fragments, on the other hand, are actually rather common and can be found in many formations. One main reason eggshell is relatively abundant compared to complete eggs is that a single egg when broken can become dozens of fragments. Geographically eggs so far were found in Argentina, Canada, China, Columbia, France, Great Britain, India, Kazakhstan, Mongolia, Peru, Portugal, Romania, South Korea, Spain, Switzerland, the United States, and Uruguay. Within Canada, eggs are exclusively found in Alberta. Within the USA, eggs have been found in Colorado, Idaho, Montana, New Mexico, South Dakota, Utah, and Wyoming. The vast majority of eggs are found in Asia. Additional information: http://www.ucmp.berkeley.edu/science/eggshell/eggshell4.php Did dinosaurs care for their young? It seems that many dinosaurs did in fact care for their young. Evidence for this has been found on multiple continents. There is still debate over the type and amount of care the parents may have provided. There are two major variations in care being debated, and these come down to whether the offspring were altricial or precocial. See the list of terms near the end of this guide for definitions. One possibility is that a group of adults would use cooperative breeding to care for a clutch, this is basically the village raising a child approach. With theropods, in particular Oviraptor, the presence of adults on eggs does support incubation and possibly even brooding. Hatchlings have been found within a nest and could have died there for many reasons, brood reduction and siblicide are both entirely possible. Given the diversity of dinosaurs, it is likely different dinosaurs provided varying levels of care for their young. Modern example showing a female crocodile providing care: Modern example of a spoonbill bird raising young: Some dinosaurs such as the sauropod titanosaurs, likely did not care for their young but rather used the same strategy as sea turtles. A large group of females would lay hundreds of eggs at once to overwhelm the predators and just by sheer numbers allowing some of the babies to live to adulthood. Are there any diseases or mutations of eggshells? Yes, we have paleopathologies found in eggshell. Paleo meaning ancient and pathology being the study of diseases, so paleopathology is the study of ancient diseases. One of the more common is where two or more layers of eggshell overlap in a way where the pores no longer pass through the entire shell, this reduces the amount of oxygen an embryo can receive. Too many of the pores being misaligned can be fatal. What color were eggs? One of the most recent breakthroughs in egg research is an ability to determine colors present within fossilized eggshell. Interestingly, from the eggs so far examined there seem to be many colors and patterns. With this being rather new to the field, not many eggs have been tested plus there is likely some error and bias. Even so, there are remarkable results. Some eggs were simple, just white. Some were speckled. Many were dull earthy colors, while others were green and blue. Given their close relationship, it is logical to assume dinosaur eggs could show any variations of what we see from either crocs or birds. Modern crocodiles have white eggs whereas modern bird eggs range in color and pattern. Interestingly, even within the same bird species there is a range in color, so it is entirely possible dinosaur eggs from the same species also vary in color. Three modern chicken eggs showing variation in colors and size. From Wikimedia Commons What is working with eggs like? Fieldwork: The basic process of removing eggs from the ground is very similar to that of removing fossilized bones. The approximate size of an egg is figured out and then the area around it is trenched until a plateau is formed. Next, a plaster jacket is made encasing the plateau. The bottom of this is removed until the whole thing can be “popped.” After which it is flipped and then is ready to be brought back to the museum. An egg at a new nesting site just after I uncovered it. Pic from the Two Medicine Dinosaur Center Jacketing an egg at Egg Mountain in Montana. Pics by D. O’Farrell. To find small fragments of eggshell and embryonic bones, removed rock is often sifted. Since they are so small—and also a rock surrounded by rocks—many times until sifted, the tiny bones or eggshell are not visible. Sifting for eggshell, here I am showing Paleontologist Barbie an example eggshell fragment. Pic from Coffeewithhallelujah After viewing the example fragment, my esteemed colleague Paleontologist Barbie was able to find an eggshell fragment. Can you find the piece of eggshell below? Pic from Coffeewithhallelujah Preparing and reconstructing an egg: Eggs tend to be more tedious and require more patience than normal prep work. Eggs are not that difficult to prepare, however, to an even greater extent than bones, they are very unforgiving. Reassembling a fossil bone after a mistake is not necessarily easy, however it is normally possible. The same often cannot be said for fossilized eggs. If you ever want to try and reconstruct a dino egg, just save the last chicken egg after cracking it and then try to reassemble. Remember, chickens are dinosaurs and their eggs make a decent modern analog to a classic theropod egg. Eggs in context- The Two Medicine Formation: To bring us all the way back to the beginning, what is the importance of studying eggs? Why bother? The primary geologic formation I have spent the last seven years working in is the Two Medicine and in terms of eggs, it is the most significant location in North America. One newly discovered nest I am fortunate enough to have an ongoing role in excavating and scientifically describing. From eggs and embryonic remains, the ecosystem of the Two Medicine is relatively well known compared to nearly every other formation. In terms of paleoecology, nesting sites show where adults felt safe and secure with enough food, water, and other resources. Within this formation was true evidence for parental care, particularly care in the form of nurture similar to birds. Behavior is nearly impossible to deduce from the limited fossil record, yet the care for young is strongly supported thanks to discoveries in the Two Med. Three dinosaurs from the formation have been linked to their eggs, Hypacrosaurus, Maiasaura, and Troodon. It may not seem impressive but three dinosaurs with embryonic remains is a truly remarkable find and incredibly rare. Even now, after over forty years of study, the Two Med continues to surprise with new nesting sites. Read about how the Two Medicine and Maiasaura was discovered: Additional information: http://www.ucmp.berkeley.edu/science/eggshell/eggshell_case1.php https://www.nps.gov/articles/mesozoic-egg-mountain-dawson-2014.htm https://serc.carleton.edu/research_education/mt_geoheritage/sites/augusta_choteau/paleontology.html http://www.georgialifetraces.com/2014/07/15/tracing-the-two-medicine/ http://www.georgialifetraces.com/2014/08/04/fossil-visions-in-the-two-medicine/ Hear me talk about my research on eggs and Troodon: Dinosaurs as living animals: Eggs allow us to see these animals as just that, animals. There is a reason many feel sad when seeing a baby dinosaur still in its egg, yet the same sadness tends to not be shown for adults. Why? The poor baby was deprived of an actual life and it is easy to relate. When covering a natural disaster, one goal of reporting is to humanize the story. In a similar way, when reporting on dinosaurs, it is important to try and do the same. Eggs allow us to come far closer to dinosaurs as true animals than I feel we ever will through bones alone. Eggs and reproduction give a window into the lives of these wonderful animals. When trying to describe what separates something living from an inanimate object, the ability to reproduce is used as a major criterion, therefore making it one of the most important aspects of dinosaurs to study in detail. Some Relevant Terms: These typically are used for modern birds and the classic theropods. Altricial: A developmental classification where at hatching, the offspring are relatively immobile, lack feathers or down, have closed eyes and are completely dependent on their parents for survival. Altricial birds include herons, hawks, woodpeckers, owls, and most passerine songbirds. Brood (n): The offspring of an animal which are hatched or cared for at one time. Brood (v): To sit on and keep warm. Brooding: To sit on and keep offspring warm when they cannot maintain their own body temperatures. Brood reduction: A reproductive strategy where the female lays more eggs than can be cared for and raised. The smallest and weakest of the brood typically starve or are killed by siblings. Clutch: Total number of eggs laid by a female in one nest attempt, often 3 or more. Conspecific: Of the same species. Cooperative breeding: Breeding system where non-parental adults assist other breeding pairs (usually their own parents) to rear offspring, instead of dispersing from the nest or breeding themselves. Incubation: The process by which parents keep eggs at the proper temperature to ensure normal embryonic development until hatching. In most cases, birds sit on eggs and transfer their body heat through a patch of skin known as the brood patch. In many species, only the female incubates; in other species, both males and females incubate. Less common is where only the male incubates. Precocial: Offspring are capable of a high degree of independent activity immediately after hatching. Precocial young typically can move about, have their eyes open and will be covered in down at hatching. They are generally able to walk away from the nest as soon as they have dried off. Siblicide: The death of a young animal usually as a result of fighting with siblings over food, common in years when food is in short supply. Further reading and information: https://www.amnh.org/our-research/paleontology/about-the-division/more/fossil-identification/dinosaur-eggs-fossil-identification http://www.ucmp.berkeley.edu/science/eggshell/index.php http://www.ucmp.berkeley.edu/science/eggshell/eggshell_hirsch.php http://www.ucmp.berkeley.edu/science/eggshell/eggshell5.php https://feederwatch.org/blog/raptors-make-good-neighbors-hummingbirds/ Images: University of California Museum of Paleontology: http://www.ucmp.berkeley.edu/ Yang et al. 2018: https://doi.org/10.7717/peerj.5144 Montana State University: http://www.montana.edu/ Two Medicine Dinosaur Center: http://www.tmdinosaurcenter.org/ Royal Tyrrell Museum: http://tyrrellmuseum.com/ Museum of the Rockies: https://museumoftherockies.org/ The Zuhl Museum: https://zuhlmuseum.nmsu.edu/ Dr. Tony Martin: http://www.georgialifetraces.com/ Mueller-Towe et al. 2002: https://www.researchgate.net/publication/260391508_Hatching_and_infilling_of_dinosaur_eggs_as_revealed_by_computed_tomography University of Calgary Hadrosaur eggshell: https://www.ucalgary.ca/drg/imagesort/00S000500 Oviraptor eggshell: https://www.ucalgary.ca/drg/imagesort/00S001300 Varricchio et al. 1997: https://www.researchgate.net/publication/232793785_Nest_and_egg_clutches_of_the_dinosaur_Troodon_formosus_and_the_evolution_of_avian_reproductive_traits Coffeewithhallelujah: http://coffeewithhallelujah.blogspot.com/2015/07/paleontologist-barbie-at-two-medicine.html Wikimedia Commons Citipati: https://en.wikipedia.org/wiki/Citipati Chicken eggs: https://en.wikipedia.org/wiki/Egg_as_food List of open access egg related papers: Thanks to the late Joe Gallo for this wonderful list. Disclaimer: For legal purposes, it should be noted links to an institution does not constitute endorsement by the respective institution and pictures are used here for educational purposes only. All rights belong to their respective owners. From the 2018 SVP meeting, my poster, which was a presentation on new dinosaur eggs. Pic from the Two Medicine Dinosaur Center Many thanks to J. Cozart and L. Murphy for writing some sections as well as edits. Thanks to D. Lawver, Ph.D. for reviewing the information presented. I especially would like to thank @Fossildude19 for assisting me and additionally thank these members for input and suggestions: @Troodon . @Seguidora-de-Isis . @HamptonsDoc . @-Andy- Eric P.

The Basic Dinosaur Egg Guide Many people often mistake a concretion for an egg, to help clarify what is a concretion, and what is a real egg, here is a guide. A quick overview with examples: How to spot a concretion: How are they different from eggs? A concretion is a rather common rock made of tightly compressed minerals. Typically, concretions are a smooth sphere or oval with little to no surface texture or just a few bumps. Often nearly a perfect sphere, sometimes more of an oval. In a concretion, there is no eggshell. If you cannot see eggshell then you do not have an egg. If it looks the same shape as modern egg, such as from chicken then you do not have an egg. Concretions may have fragments breaking off and these will tend to be smooth on both sides. They tend to be dull earthy colors with a different composition in the center, as seen by a change in color. A different color in the center normally means you do not have an egg. Often circular bandings can be seen around exterior of concretions. Sizes of concretions range from just an inch, or a few millimeters, up to more than 10 ft (3 m). Egg sizes, along one side, range from just an inch or a few millimeters and top out at around 8 in (20 cm). If you find an oval or round shape, which is larger than 8 in (20 cm) along a side then it is probably not an egg. For more information on concretions: https://www.priweb.org/index.php/education/education-projects-programs/earth-101/concretions http://tumblehomelearning.com/geologists-find-largest-dinosaur-eggs-in-the-world-another-fraudulent-fossil/ https://en.wikipedia.org/wiki/Concretion In video form: https://www.youtube.com/watch?v=B5IoyLEwkMY Example of concretions, these three were incorrectly given an ID as “dinosaur eggs” however they are clearly not: From Tumblehome Learning, link above Pseudofossils: There are some pseudofossils, which can have a similar appearance to an actual egg, right down to seeming like there are bits of eggshell. This pseudofossil does look similar to an egg and even seems to have eggshell, however it is not an egg and is actually geologic. The surface ranges too much in texture and composition. Pic from Montana State University, taken by P. Germano Trace fossils: Many times, an actual trace fossil can be mistaken for an egg, common examples of this are pupa cases and cocoons. As one can see below, they do tend to have an egg-like shape and are yet another perfect example of why shape alone should not be used when trying to identify eggs. The three below are important trace fossils, just not eggs. Pic by Tony Martin, Ph.D. How to spot a real egg: The best and only true sign you have an actual egg is eggshell actually being present. Eggs come in many shapes from a semi-rounded, elongated oval to a perfect sphere and many others. Shape is not a good indicator of an egg. It is useful but only when combined with other details. Eggshell often has surface ornamentation that gives it a unique texture which can be seen by the naked eye or with a hand lens. There are many such ornamentations and they are used to help distinguish one egg type from another. On the surface look for little bumps, ridges with valleys, river channels, and similar textures. Individual fragments of eggshell are rather common in some geologic formations so be on the lookout for a larger grouping of eggshell. From University of California Museum of Paleontology Also read: http://www.thefossilforum.com/index.php?/topic/59654-dinosaur-eggs-lowell-carhart-guide/ Examples of real eggshell: Example of eggshell fragments: An eggshell fragment from Maiasaura, which is the oogenus Spheroolithus oosp. Pic by W. Freimuth. Examples of real eggs: A clutch of Troodon formosus eggs, which are the oospecies Prismatoolithus levis. Pic from Museum of the Rockies Do I have embryos inside this egg? Most likely no. Embryonic remains are extremely rare within eggs, and you add that with the rarity of eggs to start and it is a remote possibility. No fossilized yolks have been found and since they are soft tissue, it is near impossible for any to fossilize. I still think this is an egg! If you still think you have an actual egg, then please start a thread. Take close detailed pictures with something for scale such as a ruler and provide all the information you can about it--like where it was found. Good pictures will help greatly with a proper and correct ID. Below is an example of how to best photograph an egg or eggshell. There is clear lighting, a background which is clearly different than the eggshell in question and a scale bar. Lights can be as simple as a desk lamp; a scale bar can just be a ruler and the background can be very simple, in the example just a paper towel. Megaloolithus egg. Pic from Montana State University, taken by P. Germano If you would like to learn much more on eggs, here is the advanced egg guide which goes in depth. Also, see the advanced guide for sources. Eric P.

I was wondering what this was? I believe it may be a concretion but I am unsure, and may be misidentifying it.

I made a trip to bison creek yesterday. Not it’s real name, but where I found the bison. So it seems an apt name. I packed my backpack and hip waders in my trunk and headed out. I got a half mile down the road and realized I’d forgotten to bring a change of pants. I told myself “I’m running late. I’ve got my hip waders to cover my pants. I’ll be fine. I only had 2.5 hours to explore, splash around the creek and play with any new fossils or rocks I might find of interest. I needed to leave by 3:00 so I could go to a send off party for a friend who is going to go minister to the Lakota tribe in South Dakota for 2 years and hopefully establish a thriving Celebrate Recovery group there. Anyway, as I was putting on my waders I could see sunlight passing through in a few places. I guess they weren’t made for kneeling and digging and excavating fossils. I got my gear and headed down to the creek. It was bright and sunny and in the low 50s. Great weather for hunting. I stopped by the bison dig on my way downstream. The last cavity I had dug the articulated leg out of had collapsed in on itself. We had rain one day last week so I’m sure that helped it along. I thought I’d dig through some of the old collapsed dirt where I’d found bones before. I found one more vert. Hard to tell, but there is bone there. I moved on down the creek. There aren’t many obvious fossils in the creek, but there are lots of cool rocks, concretions and minerals. If you know me I’m fascinated with concretion. Here is a view of the creek. Notice the layers on the right. The gray extends 3-4 feet up into the bank. Then the Pleistocene layer begins. There is s small tan layer. I think the Pleistocene begins above that. Here is a cool looking septarian concretion. I call these turtle rocks. They’re aren’t turtles, but that’s what they reminded me of. It has strong mineral veins of brown, most likely aragonite running through it. The other side. I like the richness of color. It’s probably just iron stain, but I like it. Most septarians around these parts are a dull gray. I walked a little further and came to this part of the creek with a high bank. This area seems to be a geological irregularity of some kind. This may be one of those instances where it lies in unconformity or something like that. I know for sure the dark gray is Eagle Ford Group, Arcadia Park Formation I believe. The light layer above it up to the next gray layer is either Austin Chalk or Eagle Ford. It could be a layer of Austin Chalk, which becomes more dominant to the east. The Austin Chalk overlays the Eagle Ford. Then above the tan a thin layer of gray where it is Pleistocene. The tan layer thins out to the right and disappears altogether a few feet to the right of the pic. There is a big chunk of light gray shale that had fallen from the bank. Concretions are scattered along inside the bank. Some quite large, very cool and pretty. There are frequent avalanches and here you see evidence of that on the left. There is a concretion in the creek probably from the avalanche. I think I’d be just as happy sitting curiously breaking open the concretions and studying them. They’re just fascinating! Of course then I’d want to take them all home. The creek bed is a slippery shale. I think this is so cool looking! The cavities are filled with a druzy type calcite with some aragonite too. I’m not use to seeing small little ones like that. The ones I find near Dallas are huge and not druzy. The size of these overall though are huge. Here is s close up of part of it. I didn’t attempt to take any of it. I couldn’t carry it, but it sure is pretty. Also, this is s high avalanche risk area. It concerns me more than the NSR in terms ov avalanche risk. In this area there are lots of minerals oozing out in places. It colors in the shale. I have been told there is fish fossil material in this creek. I haven’t found the exposure yet though. This piece on the bottom right looked fishy to me. There are other parts that looked like it had scales and also the pattern of fish scales was scattered across the piece at the top center. I’m not sure what it is. It is in fine delicate shale though. There was this white gelatinous substance that looked to be oozing out of the rocks in places. Very weird looking. I don’t recall seeing such a thing before. The bank is streaked with minerals that have been in solution and flowed down. Some looks like sulfur yellow. Some orange and white. There are also fine calcite and possibly gypsum crystals in the layers. Some like fine needles. They may be some other mineral too. Anyone know what the white stuff is? It was oozing out of a long vein across the creek. There was another area where the rock and water were stained orange from what looked like iron leaching out. This septarian is over 5 feet long. I moved on down the creek. There was a large gravel bar just down the creek filled with septarian nodules both whole and fragments. This one isn’t too pretty, but I think it has potential. Maybe a weak acid wash would brighten it up. It looked predominantly aragonite. You don’t see many like that this big. I kept moving. On my left was a sand bar where the Pleistocene layer was at the surface. I spotted an odd looking thing that looked a bit like an exposed root. I went to check it out. Woohoo! A bone or a fragment of one. I put down my pack and pulled out my chisel to remove the dirt around it. Bones can be fragile. I could just pull it out, but I risk breaking and losing some of it. So I always dig around bones or fossils to free them up before pulling them out. It kind of looks like the distal end of a humerus, but I’m not sure from what. The epicondyles are broken off the other side and it’s pretty worn. Ill post more later. I’m not half done yet.

The open access paper is: Clements, T., Purnell, M. and Gabbott, S., 2018. The Mazon Creek Lagerstätte: a diverse late Paleozoic ecosystem entombed within siderite concretions. Journal of the Geological Society. Journal of the Geological Society (2018) 176 (1): 1-11. https://doi.org/10.1144/jgs2018-088 https://pubs.geoscienceworld.org/sepm/jgs/article/545488/the-mazon-creek-lagerstatte-a-diverse-late https://pubs.geoscienceworld.org/jgs/issue/current Another open access paper is: Briggs, D.E., Liu, H.P., McKay, R.M. and Witzke, B.J., 2018. The Winneshiek biota: exceptionally well-preserved fossils in a Middle Ordovician impact crater. Journal of the Geological Society, 175(6), pp.865-874. https://pubs.geoscienceworld.org/jgs/article/175/6/865/548502/the-winneshiek-biota-exceptionally-well-preserved https://pubs.geoscienceworld.org/jgs/issue/175/6 Yours, Paul H.

Ok, when I wake up, drowzy, make some coffee, then into the computer room. This is what I see. Lots more in the display cases behind me with no room left! Then I open the top drawer, more crab fossils, forgot about those. Lots more in the garage! then I realize, there are two more in the glove boxes of my 2 trucks. Now I wonder where else I have more? We all have problems. We all need help. but for me, Im not sure how I can find a cure? But for now, I will just smile and go on. This is a problem I can live with. All I need now is more to prep. Do I have a disease? RB

Ive decided to start a crab prep thread instead of doing a post for every single crab I prep. If it works, great. If not, then I will go back to seperate posts for each. I will start with this one that I just started today. This is Pulalius vulgaris from the state of Washington and Eocene in age. This was 'Whacked' open by my youngest son. Turned out to be a purty good whack. This first picture is with the top piece of rock tossed away and the 2 pieces you see on the side are pieces from the bottom of the rock. You can easily see how the crab is not situated correctly in the rock. Not usually a good thing? There is almost always a reason for this. These next two pics are gluing the pieces back onto the bottom of the concretion. This way the concretion will look complete. I ALWAYS save all the pieces just in case! Now I have a complete bottom half of this concretion. There was a small crack and I very softly and carefully pried it off exposing quite a bit more of the crab but it also took a part of the arm off the crab. Had to glue it back on. Not a big deal, just a tad bit more time. And now after a few hours of scribe prep, its easy to start to see all the problems. Very tuff to get an A-Grade crab!!! There seems to be no left claw to speak of. Also looks to be only a 4 legger. There might be another one in there somewhere but its not looking good. But really, so far, it may be a purty good one clawed 4 legger crab? The preservation is really nice!

Hello everyone, I am in desperate need of help with a huge debate I have been having with a friend over fossils preserved in ironstone concretions. From some of what I had read to some advice from other members I it possible to find vertebrate bone among shells and other mollusks preserved in an ironstone concretion. Whether it leaves a trace of the organism, morphs the organic material into the structure of the iron concretion through the decomposition with preserving, or whatever else it may be it seems to be possible. So recently I have hunted a place known to have recorded marine cretaceous shell and other mollusk found in ironstone concretion as well as cretaceous plants in shale, it seems like not to vast of enough study has been done there only from what I know, but since no vertebrate material had yet been discovered there though there can maybe be the possibility. I found these two particularly distinct pieces in iron concretions that exactly mimic the scute structure of soft shell turtle and croc in my opinion, I know how iron concretions are famous for leaving psuedofossils and such but these two pieces look way to exact and since its possible for shells and mollusks to preserve why not scutes? So I am here looking to end this debate, I'm looking for your opinion, can these be labeled as fossils, traces, etc? Or are these among some of the world's best iron concretions and nothing more. Your input especially if you are very experience in this subject would be tremendously appreciated.

Hello I present an interesting question that I'm not to confident to answer myself and am seeking help from the more knowledgeable. Since it seems like (from what I had seen) iron concretions can at rare times preserve certain fossils or traces in one way or another such as molluscs, brachopods, and such. Due to this would it be possible for material such as turtle shell scutes or maybe even croc scutes to turn up in such concretions in one way or another? (the pics are just snipets of general info that I came across online)

Well, I started my first Lincoln Creek Formation concretion prep. I'm hoping for a crab. I purchased a used CP 9361. I took it apart and checked the o rings and cleaned up the extra oil from the previous owner. It's missing the lock ring, but other than that it seems to work fine. I've been reading this forum as much as possible, and these are the other things I'll be getting or making: 1. I'll be calling Paleo Tools and ordering a new front end with a 2" chisel, as well as getting a Microjack 6 with a 2" point. 2. I have eye protection, but will be getting new ear muffs and dust mask. 3. And I'll make a frame to support and hold the concretion, while working on it. Any suggestions for additional items I might need or want? After removing my first 1/1000th of an inch of matrix, I can't wait for my next 15 minute work session!