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I don't throw around the word "best" casually, but I think it's safe to say that my recent trip was one of the best in all my years collecting, if not the best. I spent the better part of five or six hours collecting at numerous different sites across western Maryland ranging in age from the lower Devonian to the lower Mississippian, so this is part one of my posts (for simplicity's sake I may include photos of most of my other finds from these sites even if I didn't collect them last go around).

 

The trip started off okay. I visited a couple of my oldest sites that are some small roadside exposures of the Oriskany Sandstone and Mahantango Formation. These sites produced decent material in the past, but over the repeated years of collecting I seem to have worn them out as this time all I found were some brachiopods (including a decent Mucrospirifer sp.  from the Mahantango site). I'll talk more about these finds later, but afterwards I found time to visit a new site in the Brallier Formation. By this point it had started to thunder, and while driving to the site the rain started to come in and fog filled up the valley. I thought it was the end of my trip, but as I got to the site it was pretty much dry. My best guess is that I was simply hearing a storm from way off in the distance. 

 

The site I visited, as I recently learned, might actually expose two different formations: the Brallier Formation and the Foreknobs Formation. The difficulty in discerning between the various upper Devonian formations in Maryland is multifold. First off, the MGS doesn't differentiate the Harrell, Brallier, and Scherr Formations, even on their most recent geologic maps. Second of all the literature around these deposits is scant and very dated. Most still use the (now) incorrect Woodmont and Chemung Formations, which further exacerbates problems as the Woodmont Formation consisted of the current Brallier and Scherr Formations, making it difficult for an amateur like me to really tell just which fossils occur in either formation. On top of this the contact between the Harrell, Brallier, Scherr, and Foreknobs is mostly gradational, so the differentiating layers lithologically is next to impossible as the beds gradually blend into one another. Generally speaking the Harrell is a dark shale with a fossiliferous limestone (the Tully Limestone) demarcating it's base, the Brallier is mostly dark, fissile shale with interbeds of siltstone, the Scherr is mostly lighter colored shale and siltstone with some sandstone beds, and the Foreknobs is a mixture of gray shales, red shales, conglomerate, sandstone, and siltstone.

 

A guide fossil for the Brallier is the brittle star trace fossil Pteridichnites biseriatus, which was the fossil I originally set out to collect and found in the darker shale. Generally speaking the brachiopod genus Cyrtospirifer sp. in particular C. disjunctus is a guide fossil for the Foreknobs, but I believe this genus also occurs in the Brallier Formation. I found both fossils at this site, the brittle star in the dark shale and the brachiopod in a reddish siltstone, and considering the transition in rock types (one end of the site was just dark, fissile shale and the other had significant amounts of conglomerate and siltstone with shell beds) I think it's likely that the upper end of the cut was in the basal Foreknobs Formation and the lower end was in the upper layers of the Brallier Formation. As such, all of my trace fossils are from the Brallier and almost all of my other fossils are from the Foreknobs. 

 

The Brallier Formation is a late Devonian turbidite unit that was deposited in fairly deep water as the Acadian Mountains eroded. It is mostly unfossiliferous, but does have the occasional pelycopod, gastropod, and trace fossil (these being the most common). Ammonoids are also reported from the Brallier. Like I said earlier I originally came trying to find the brittle star trace fossil Pteridichnites  but I ended up finding some other very interesting trace fossils. I picked up two of them because I had seen images of similar looking things from the Pennsylvanian of Alabama which I believe @Rockin' Ric labeled as resting traces from horseshoe crabs.  These are late Devonian, deep water marine in origin, not terrestrial/freshwater from the Pennsylvanian, so I don't really know what they could be. Perhaps from some other arthropod? Anyways I also found some brittle star traces, including a group of what look to be four or five Pteridichnites biseriatus oriented in life position as if it were an imprint of the brittle star body. 

 

Image 1: Pteridichnites biseriatus

Image 2: A group of four poorly preserved P. biseriatus 

Image 3: Unknown arthropod (?) trace fossil

Image 4: Unknown arthropod (?) trace fossil 

 

If any of you guys know what the last two fossils are, please feel free to let me know. 

 

 

 

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The Foreknobs is a shallower water deposit, also late Devonian in age. It is much more fossiliferous than the Brallier, and at this site there were beds over a foot thick composed of hundreds of brachiopod and pelycopod shell fragments. But this time the Foreknobs had something I have never seen before in Maryland - a fish bone and teeth! After all these years I have finally found a piece of bone! One of the sandstone boulders I saw had a piece of blueish white bone in it. I took a picture of it, but I'm having trouble uploading the picture so I'll come back later when I get the photo of it. Funnily enough the fish bone was one of the first fossils I found at the site, so I immediately stopped looking for brittle stars and instead focused for fish bones. I spent the better part of thirty minutes looking around the boulder for other pieces of bone and teeth, but all I found were some possible scales and what looks like it could be a tooth, but I'm no expert. 

 

Image 1: It looks like it could be a starfish/brittle star imprint? It appears to have outlines of three arms. I found this near the transition of the Brallier and the Foreknobs, so it could be either formation (I'm leaning towards Brallier). 

 

Image 2: Trilobite thoracic segments, likely from Eldredgeops sp. I found this fossil while going over my finds when I got back home, which was a nice surprise. Trilobites, even fragments like this, are pretty rare from Maryland, and a late Devonian specimen is rarer still. 

 

Image 3: Could it be a tooth? It has a weird texture (kind of wrinkly) that makes me think it's not a burrow, and considering I found the fish material nearby I was inclined to keep it just in case. 

 

Image 4: A tiny brachiopod, Tropidoleptus carinatus

 

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Image 1: Looks to be a Tropidoleptus carinatus.

 

Image 2: A plate containing several brachiopods, including Tylothyris mesacostalus

 

Image 3: Buchiola sp. 

 

Image 4: Tropidoleptus carinatus. 

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Image 1: Cyrtospirifer disjunctus (?)

 

Image 2: Cyrtospirifer disjunctus (?)

 

Image 3: Maybe an ammonoid? Or it could be a gastropod. 

 

 

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Image 1: Maybe a mold of a starfish? 

 

Image 2: Crinoids. 

 

Image 3: Crinoid. 

 

Image 4: Pelycopod. 

 

Image 5: Pelycopod. 

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Image 1: Hash from various shells and crinoids. 

 

Image 2: A nice hash plate of various crinoid parts. I actually found this sitting on the shoulder while walking along the road. 

 

Image 3: Close up of above. 

 

Image 4: One of the possible scales, from the same rock with the possible tooth. 

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It looks like you made some nice finds.  You might achieve sharper images if you placed them on a stable surface.  Hand-held items compound focusing issues.  ;) 

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I really like your post, @EMP, and the material is quite interesting. Trace fossils are quickly becoming some of my favorites, I think due to their often mysterious origins.

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1 hour ago, EMP said:

 

Image 5: Pelycopod. 

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I bet this is a type of Crinoid, strange one though. From Here

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Amazingly informative post! Awesome finds too, especially the trilobite!! I’ve been thinking about those traces, and they really are strange. 

About your tooth, I don’t know if it is one. It doesn’t have any enamel. I wonder if it may be a fish coprolite though. If not, could just be a sedimentary structure.

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8 minutes ago, WhodamanHD said:

Amazingly informative post! Awesome finds too, especially the trilobite!! I’ve been thinking about those traces, and they really are strange. 

About your tooth, I don’t know if it is one. It doesn’t have any enamel. I wonder if it may be a fish coprolite though. If not, could just be a sedimentary structure.

 

Yeah, I'm also pretty skeptical of it being a tooth. It's not at all like the others I found in the boulder, those were smaller and shiny black. Maybe @GeschWhat could help to confirm if it is a coprolite or not. 

 

 

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13 minutes ago, EMP said:

 

Yeah, I'm also pretty skeptical of it being a tooth. It's not at all like the others I found in the boulder, those were smaller and shiny black. Maybe @GeschWhat could help to confirm if it is a coprolite or not. 

 

 

Hard to tell if it is a coprolite. I'm leaning more toward the negative. Most coprolites will be comprised of material that differs from the matrix. Yours almost looks like a cast of something. :headscratch:

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Part two. 

 

Usually this site is one I make sure to hit when I'm in the area, and is also one of the older sites I've been collecting at (or rather was). It used to be a decently sized exposure of the Needmore Shale but after a visit in the spring of 2017 I was not so pleasantly surprised to see that the most productive layer had been buried in feet of wood chips and talus (darn SHA always ruining the fun :P). Luckily I had plenty of time to collect at it before it became closed. 

 

The Needmore is rather hit and miss in terms of fossils. The general rule at this site was that the cream colored shale/siltstone tended to be the most fossiliferous, but even then you could go an hour of collecting without finding much more than a handful of brachiopods and tentaculites. However this site was one of my favorites because it was one of only two sites that regularly produced trilobites, even if they were just tiny bits and pieces. I'm sure our Maryland collectors would be able to vouch for how hard it is to find such a thing in the state. 

 

The Needmore is mostly early Devonian in age, but near it's contact with the overlying Marcellus Shale it becomes middle Devonian in age. It was deposited in a shallow water setting, with remnants of reef like environments being present in some places, though there are layers that were likely deposited in deeper water (but not nearly as deep as the Brallier). It is also the basal member of the Hamilton Group in Maryland, which represents the entirety of the middle Devonian in Maryland except for, I believe, some of the basal layers of the Harrell Fomation. 

 

I didn't find any trilobites this round, but here are those that I found over the years. 

 

Image 1: Cephalon of a Eldredgeops rana. Note the eye. 

 

Image 2: Part of a thorax of a trilobite, likely a Eldredgeops rana. Upon looking at this specimen further, the outline of the pygidium appears to be visible from underneath the shale, so it's likely that most of the animal is there save for parts of the cephalon. 

 

Image 3: Thorax and pygidium of a trilobite, likely a Eldredgeops rana. 

 

Image 4: Thoracic segments of a trilobite, likely an Eldredgeops

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On 8/8/2018 at 11:35 AM, EMP said:

Part two. 

 

Usually this site is one I make sure to hit when I'm in the area, and is also one of the older sites I've been collecting at (or rather was). It used to be a decently sized exposure of the Needmore Shale but after a visit in the spring of 2017 I was not so pleasantly surprised to see that the most productive layer had been buried in feet of wood chips and talus (darn SHA always ruining the fun :P). Luckily I had plenty of time to collect at it before it became closed. 

 

The Needmore is rather hit and miss in terms of fossils. The general rule at this site was that the cream colored shale/siltstone tended to be the most fossiliferous, but even then you could go an hour of collecting without finding much more than a handful of brachiopods and tentaculites. However this site was one of my favorites because it was one of only two sites that regularly produced trilobites, even if they were just tiny bits and pieces. I'm sure our Maryland collectors would be able to vouch for how hard it is to find such a thing in the state. 

 

The Needmore is mostly early Devonian in age, but near it's contact with the overlying Marcellus Shale it becomes middle Devonian in age. It was deposited in a shallow water setting, with remnants of reef like environments being present in some places, though there are layers that were likely deposited in deeper water (but not nearly as deep as the Brallier). It is also the basal member of the Hamilton Group in Maryland, which represents the entirety of the middle Devonian in Maryland except for, I believe, some of the basal layers of the Harrell Fomation. 

 

I didn't find any trilobites this round, but here are those that I found over the years. 

 

Image 1: Cephalon of a Phacops rana. Note the eye. 

 

Image 2: Part of a thorax of a trilobite, likely a Phacops rana

 

Image 3: Thorax and pygidium of a trilobite, likely a Phacops rana. 

 

Image 4: Thoracic segments of a trilobite, likely a Phacops. 

FYI: Phacops rana has been reassigned to Eldredgeops rana in North America by Struve in 1990.

 

Struve, W. (1990)
Paläozoologie III (1986-1990).

Courier Forschungsinstitut Senckenberg, 127:251-279

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Image 1: Glabella of a Eldredgeops rana. I actually found this by randomly hammering a rock I had brought home, so I guess it does pay to just whack it! 

 

Image 2: Imprint of the thorax of a trilobite, likely a Eldredgeops rana.

 

Image 3: Enrolled thorax and pygidium of a Eldredgeops rana. 

 

Image 4: Enrolled thorax and pygidium of a Eldredgeops rana. This one is probably my favorite of all the trilobites from this site. 

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Image 1: A plate with both some thoracic segments of a Eldredgeops rana trilobite and the imprint of a brachiopod, I believe Tropidoleptus carinatus

 

Image 2: A Tentaculites sp. with some assorted hash around it. 

 

Image 3: Devonochonetes sp. with a nice pelycopod alongside it. 

 

Image 4: Spirifer (?) sp. at any rate a spiriferid, if anyone knows the actual ID please feel free to let me know. 

 

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Image 1: Devonochonetes sp. 

 

Image 2: Unidentified pelycopod.

 

Image 3: Unidentified pelycopod, both valves present! 

 

Image 4: Unidentified gastropod. 

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23 minutes ago, EMP said:

I'm sure our Maryland collectors would be able to vouch for how hard it is to find such a thing in the state. 

*raises hand* :D

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Fossildude19

The gastropod is an internal cast, but could be Bembexia sp. 

 

Paleoniello sp.?                                                                                                          Paracyclus rugosa

 

 

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44 minutes ago, Fossildude19 said:

The gastropod is an internal cast, but could be Bembexia sp. 

 

Paleoniello sp.?                                                                                                          Paracyclus rugosa

 

 

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Thanks so much fossildude!

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The Oriskany Sandstone is a very fossiliferous quartz sandstone of early Devonian age. In this part of the Appalachians it is a major ridge forming unit, holding up the caps of such ridges as Tonoloway Ridge, Fort Hill, and Martin Mountain among others. The Oriskany was actually the first formation I've officially hunted in (I visited the Calvert Cliffs before it but didn't really collect fossils there, just walk along the beach), and is also the only formation that I have visited multiple sites in. In terms of geologic setting the Oriskany was deposited in a shallow sea/beach type environment, which is evidenced by the vast amount of shells and other debris present in the sandstone. From my experience the Oriskany also has a habit of producing unusually large brachiopod specimens (possibly as the result of a selection bias against smaller, weaker shells that would have been crushed by the surf?), though I've come to find that the reported gastropods and other species are harder to find. These posts are just finds from Maryland, I have several more from a quarry in Pennsylvania (including another trilobite!) that I'll post later along with my "non-Maryland collection."

 

The most common fossils from the Oriskany Sandstone are spiriferid brachiopods, although recently I've started to come across pentamurids more and more frequently. At these sites there appear to be three species of spiriferids; Costispirifer aerenosus, Acrospirifer murchisoni, and a small, unknown one, possibly Eospirifer (?) sp. 

 

Image 1: Costispirifer arenosus. This is a common find from the formation, and an important guide fossil to it. This is my favorite specimen of this species - note both valves of the animal!

 

Image 2: A large specimen of Costispirifer arenosus. 

 

Image 3: C. arenosus. 

 

 

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Image 1: C. arenosus

 

Image 2: Unidentified wing of a spiriferid, probably Acrospirifer murchisoni

 

Image 3: Acrospirifer murchisoni. 

 

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Image 1: A. murchisoni

 

Image 2: Unknown spiriferid, possibly Eospirifer (?) sp. 

 

Image 3: Unknwon spiriferid, possibly Eospirifer (?) sp. 

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Image 1: Rensselaeria circularis (?)

 

Image 2: Rensselaeria marylandica (?) (at any rate a different species from above, and since there are only two species listed in the geologic report...) and Platyceras sp. gastropod. 

 

Image 3: Unidentified pentamurid (from what I've seen none are reported in Maryland, at least from this site). 

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