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A short while ago I unintentionally stumbled across a poorly preserved carbonized plant fossil at one of my favorite fishing streams - a place that I had never imagined would hold fossils. I posted an image of the specimen in the Fossil ID section where several members of the forum kindly confirmed my suspicions that it was a plant fossil. Here is the link to the original post in Fossil ID: @patelinho7 and I have been jointly looking into the Culpeper Basin (a Triassic rift basin within the Newark Supergroup) and its potential fossil content, and it seemed to the both of us that this could potentially be Culpeper Basin material. There were some red sandstones present that seemed to have originated from the Manassas Sandstone (a formation - or member? - within the Culpeper Basin) and the map that I inserted into the original post indicated that Bull Run Formation/Manassas Sandstone was exposed in the area where the specimen was found. However, further exploration of the site has led me to believe that the fossil originated not from the Culpeper Basin, but from Potomac Group (Early Cretaceous oxbow swamp deposits in Maryland and northern Virginia) sediments. From what I know, this could be very intriguing since the locality is in an area quite far from the traditional Potomac Group outcrop belt. However, I hope that this post and interpretations from more versed members of the forum will help establish whether these are indeed Potomac Group fossils. As a small forewarning, this will be a rather picture-heavy post. Aside from including a plethora of specimen images, I have also included images of rocks found at the stream locality in case they may help to interpret the site. Based on what I have gathered from the site thus far, my current working hypothesis is that I have found an area where a formation within the Potomac Group (hopefully someone more experienced with these fossils could shed light on whether they originate from the Patuxent Formation, Patapsco Formation, or Arundel Clay) overlies strata from the Culpeper Basin. However, this hypothesis is based solely on my observations and my limited stratigraphic knowledge and any revisions are very welcome. Before diving into the report itself, I want to thank everyone that has helped me thus far and that comments on this post. Your help and comments have greatly helped me on my quest and I would still be very clueless if it were not for this forum! To begin, I have included images of a few loose clasts that I believe may originate from the Culpeper Basin (from the Manassas Sandstone, specifically). The first specimen that I would like to mention is a piece of red, fissile shaly mudstone. The fissile nature of this specimen interested me most since most rocks I have encountered have been massive, often without clear bedding planes visible. Due to the locality being in close to the Manassas Sandstone according to the map in Dr. Weems's article (see map in the original Fossil ID post) I automatically assumed that it was one of the red sandstones from that formation. However, I have next to no experience with Potomac Group sediments and cannot say whether this may belong to the Potomac Group. Above are images of two more stones that are pretty good representatives of the general rock type found at this locality. The bottom one is another fissile mudstone much like that shown in the first image. The top specimen is a relatively flat slab of stone that seems to represent some sort of bedding plane. Loose flat slabs that resemble bedding planes are relatively common at this locality. Now, for a very shocking find! In my explorations I came across a very rare specimen of a fossilized Shoppingia cartdumpites. Unfortunately this specimen was what might be called a leaverite as it was far too large to take home and was located in relatively deep water . On a more serious note, I came across a specimen of very fissile red sandstone/siltstone. The thin layers of stone easily came apart, revealing very dark red stone within the specimen. The presence of this specimen seemed also to indicate that the Manassas Sandstone could be present at this particular locality. Now, for something a bit intriguing that could potentially represent a fossil. Unfortunately the lighting was not very good at this time of day, but there was an interesting inclusion in this piece of stone. Now, for a few more photographs before the fossils. They are a bit difficult to see due to the glare on the water, but these may be the source beds from which many of the flat bedding planes and perhaps where the fossils are coming from. I plan to add to this trip report as I continue to explore since there were a number of intriguing features that I did not photograph on my last outing. Here are a few additional things that could be important to note: 1.) When some of the rocks shown in the above photographs were flipped over, they bore a very dark red coloration. This reminded me of the oxidation that is present on some ironstones found in the Arundel Clay. 2.) Farther downstream there was a thick clay layer on the bank. This clay layer, which was composed of a whitish grey clay, was positioned between a layer of strata that coated the stream bottom and Pleistocene/modern soils. Now that I have posted some intriguing geological features, here are some photographs of the fossils that I decided to collect. Specimen 1: This is the original specimen that I posted in the Fossil ID section. Other members confirmed that it is a piece of poorly preserved wood. Specimen 2: More poorly preserved plant material. It is very hard to tell from the first photograph, so I have outlined the approximate shape of the plant fossil in the second photograph. The third photograph shows some carbonized material on the edge of the specimen. Specimen 3: An example of a stone containing a few carbonized plant elements. Stones with a few scattered plant elements are relatively common, though from my current explorations they seem to occur in rather localized areas. Specimen 4: Another indeterminate carbonized plant fossil. It is a bit larger than most of the specimens that I have found and the shape is rather different from that of most of the plants. Specimen 5: Three views of the fifth specimen: front (top image), bottom (middle image), side (last image). Specimen 6: This specimen probably represents one of the best preserved plants that I have found. However, I am not sure whether the specimen in the top image is preserved well enough to be identifiable. On the other side of the specimen a compressed plant specimen is preserved. It is difficult to tell from the photographs, but the fossil cuts diagonally across the bottom of the specimen on the lower image. Specimen 7: This plant hash plate is one of my favorite specimens of those that I recovered. Again, not sure if any members would be able to tell what these specimens may be. Specimen 8: I am entirely unsure what this specimen may be. I do not know whether these are fossils, impressions, mineral deposits, or some sort of sedimentary impressions. At any rate, the colors and depressions made for an intriguing rock. Specimen 9: A very large slab with some of the best preserved plant remains that I have recovered at this point. On one side of the slab (the first few photographs) an articulated plant seems to be preserved. This one is pretty intriguing... would any plant or Potomac Group experts have any ideas on what it may be? The other side of the slab (the last photograph) seems to contain what might be a poorly preserved plant.

Hello everyone, This summer, I’ve begun volunteering at the MNCPPC Dinosaur Park in Laurel, MD. It’s somewhere I’ve known about and visited since I was a kid, and it feels great to be a part of the park now that I’m older. For now, I planned to help out this summer as I go back to college in late August, but I’m really enjoying it so I do hope to return on breaks and after I graduate. This park is an early-Cretaceous oxbow lake deposit and is the best source of early-Cretaceous fossils on the east coast. I’ll let you do your research if you’re interested, I don’t want to go on too long. But in essence, the volunteers at the park help the public when they come on the first and third Saturdays of the month to freely surface collect (their finds are kept with the park and catalogued) to help the scientific process. We have some other duties too, but otherwise, we get to fossil hunt for several hours! It really is a dream-job for me. I’ve had this dream of finding dinosaurs close to home since being a kid, and now I get to actually live that dream. I thought I’d start this thread to show what I find over the course of this summer, and hopefully the years to come of volunteering here. I’ll start small, I’ve only volunteered for two Saturdays at the park so far, so my finds will mostly be indeterminate bone fragments, but eventually I’ll probably dial down the small stuff in the hopes I train my eye more and find better specimens. I’ll also potentially post other finds from nearby Potomac Group exposures, and I’ll give background info on all of the posts. I’m so excited to be able to post about Cretaceous fossils, so bear with me! Feel free to offer opinions and IDs, and feel free to ask me questions about what I’m doing and I’ll do my best to answer them. And if you volunteer at the park and are on the forum, please let me know!

Hi everyone, I visited one of my old MD early cretaceous footprint sites (where I found my old footprint for those who remember) just to have a look around and I found something that immediately stuck out due to its poopy appearance. I'm going to use the pinned coprolite ID guide to give some basic info before the photo dump (no pun intended). Location: - it was found in a creek around College Park, MD, an area known for Early Cretaceous ichnofossils, specifically dinosaur tracks - Formation: Patuxent Formation (Potomac Group) Shape: - It is not the most obvious poop-shaped rock, but its lack of sharp-terminating edges and lack of sedimentary layering cannot be ignored - Has a lot of interesting features that indicate it being an ichnofossil (impressions of various structures like wood), this could mean it is a coprolite, or it also could just be a freak rock that is preserving other activity Texture: - it is not granular, it's the typical ironstone/siderite found in the Potomac Group except instead of the flat, somewhat-layered ironstones typical of the Patuxent Fm - has a lot of cross hatching akin to mudcracks Inclusions: - No visible vertebrate inclusions - a couple small surface mineral inclusions (one tiny grain of what looks like quartz, one shard of what looks like chert) - interesting note: a small layer of lignite seems to be pressed into certain areas, it is the dark-brown/black flaky stuff on certain areas. This confirms it is most probably a fossil of some sort? It has the impression of the wood still on the rock behind the flakes of lignite. Could this be non-digested material? Did plant material get pressed into the excrement? Or is it a fluke bit of mud that fossilized with the wood attached? Composition: - I initially thought it could be a herbivore coprolite because I didn't see any obvious sphincter marks but *IF* it is indeed a coprolite it is way more well-defined than pictures of herbivore coprolites I've looked at - Lick test? Yeah no . I found this in a creek next to a major road in an area that definitely has runoff pollution. I am not licking that rock, haha. Thanks for taking a look! Photos: Other side with lignite presence: Both ends (cross section?):

I found this specimen recently and have been perplexed by it for a while. To me it appears to be a tooth, though if it were I don't know from what. I looked at it from under my loop and it does have some small dimples in it, and is made of shiny black material, which is what drew me to that possibility in the first place. It looks similar to teeth I've seen posted on the forum before, especially in the Pennsylvanian shark tooth topics. I did some searching and oddly enough ended up finding images from a ptychotrygon. I don't know what it is exactly, but form the images it has a resemblance to that shape. I tried taking the best pictures I could, but the object is pretty small. So I guess my questions are if it's actually a tooth and, if it is, what kind is it? It comes from the early Cretaceous Potomac Group, Patuxent (?) Formation (possibly Arundel however) from near Washington DC. Thanks for any help!

Weather was really good today so I went out hiking near my home and picked some rocks/fossils up on the way. I was along a stream the entire time, and the stream exposed sediments from the Potomac Formation, a Cretaceous deposit that has some plants and reptilian stuff in it, as well as Piedmont schist. Top down I think it's a bone fragment (?), bone/tooth/plant (?), plant, and silicified wood (??). Some of the stuff is still covered in dirt, so sorry if i's not clean/covered in mica flakes (there's a lot of that around here.)

Another flora object with unique structure.

I am going to leave this right here without comment. Prince George's County Md creek find.

I found this nice petrified wood specimen while collecting in the early Cretaceous Potomac Group sediments in Washington DC recently. It is pretty well preserved for this unit, with nice surface features, knots, and growth lines present on it.