Silurian Fossils From Maryland, Plus a Possible Devonian Bone Bed?

[EMP]

Brachiopods, including Pseudochonetes novascoticus

Upper Rose Hill Formation, middle Silurian (Wenlockian)

[EMP]

Dalmanella sp.(?)

Upper Rose Hill Formation, middle Silurian (Wenlockian)

 

Note the intricate preservation, rather unusual for sandstones in my experience. 

[EMP]

And for the piece de resistance...

 

Trilobite, Calymene sp.

Upper Rose Hill Formation, middle Silurian (Wenlockian)

 

@piranha @Fossildude19 I'd really appreciate any help identifying this guy. 

 

The specimen is inverted, that is flipped upside down, indicative of a turbulent seafloor environment. It is definitely a calymenid given the structure of the thorax and pygidium, though just what species (or even genus) I'm unsure of. Given it's size compared to the other fauna, I've tentatively assigned it as Calymene niagarensis, which is supposedly a larger species, but that's only a guess. 

 

I saw this out of the corner of my eye and thought it was some strange coral at first. Imagine my surprise when I saw it wasn't! My largest and most complete trilobite to date!

 

 

[fossilcrazy]

Hello EMP,  Very fascinating finds,. Looks like you have more areas to pour over. The fossils you have shown and the formations you mention have widespread outcrops. The same fossils have turned up but not all, of them in NY and PA. Your fish parts are easily recognizable as well as the Brachs and Ostracods.

[EMP]

26 minutes ago, fossilcrazy said:

Hello EMP,  Very fascinating finds,. Looks like you have more areas to pour over. The fossils you have shown and the formations you mention have widespread outcrops. The same fossils have turned up but not all, of them in NY and PA. Your fish parts are easily recognizable as well as the Brachs and Ostracods.

 

Thanks!

 

Is there anything I should look out for in particular? So far I've been looking for black fragments in the right kind of rock and putting those aside as "fish material." Is that generally a good rule of thumb? 

[piranha]

44 minutes ago, EMP said:

I've tentatively assigned it as Calymene niagarensis, which is supposedly a larger species, but that's only a guess.

 

 

There are still calymenids from eastern North America awaiting formal description so it might be undescribed.

A confident species ID is not possible without diagnostic cephalic features.  I would label it: Calymenidae indet.

[Monica]

A bunch of wonderful finds, but I especially like the Leptaena brachiopods 

[EMP]

31 minutes ago, piranha said:

 

 

There are still calymenids from eastern North America awaiting formal description so it might be undescribed.

A confident species ID is not possible without diagnostic cephalic features.  I would label it: Calymenidae indet.

 

Sounds good. Too bad it doesn't have an exact species but such is the game. 

[fossilcrazy]

EMP, While out hunting, I don't look for anything in particular. The neatest things were the ones that just turned up. I have black pieces in material I can identify now and others still a mystery. I have found Eurypterid pieces, not enough to pin down to a species. Have not found fish and eurypterids together. While you are out there, take home some of the Corals and Bryozoans and whatever. Those things are helpful confirming what formations you are in. My very first described fossil was a Edrioasteroid. Before I found it, I had no idea what an Edrioasteroid was. Here is my specimen (Silurian Edrios are very rare) found in a formation neighboring your Rose Hill (a member within the Keefer Ss).  

[EMP]

I've found a fair number of small, black objects like this in the quartzose conglomerate and a conglomeritic shale that is found around the conglomerate bed. The style of preservation is unlike the brachiopods in this bed, which tend to be preserved in either a yellowish iron oxide or a cast/mold of the shell in the color of the host rock. These mysterious specimens are black or dark gray/brown, and range in shape from chips like this to rounded objects. 

 

Given the occurrence of fish remains in the unit, and their mode of preservation unlike the other fossils, I'm of the opinion that there's a decent possibility they're some kind of fish remain. This one I believe may be part of a shark denticle or fish scale given the nature of it ("ribbed," for lack of a better word). It's pretty small, however, as are the other mysterious remains. 

[EMP]

These photos are from the same specimen, one taken with lighting and the other rotated and without. This is another one of several small, black pieces I collected from the talus piles at the base of the outcrop. Unlike the other specimens, however, this likely derives from the shale beds underlying the conglomerate, and the host rock lacks any large quartz pebbles typical of the fish bearing layer. I picked it up after noticing it's "bumpy" surface texture, which seemed reminiscent of placoderm armor. The object is fairly small (though still larger than the above possible denticle), made of a shiny black material, and covered in small "bumps," hopefully visible in the lighted photo. A few small structures can be seen protruding from the main mass of the object. It was associated with a few minor trace fossils, and was situated next to an unfossiliferous, partly siliceous shale that bears a variety of carbonized fragments, possibly plant and/or algal remains, not all unlike similar fragments I found in the Pocono Group of Mississippian age. 

 

It could be a part of a placoderm, which after further review a couple of placoderm pieces were reported from the "Jennings" Formation (an old name for upper Devonian rocks in western Maryland, roughly analogous to the Scherr and part of the Foreknobs by the sound of it) by MGS authors in the early 1900s. It's also possible that this could be hematite, though in that case I would mention that there is next to no oxidation typical of iron bearing shales in this layer, and the bright specks are mica flakes, not hematite grains. 

[EMP]

I found this possible tooth in a pile of refuse rock the other day. Note the many "grooves" down the length of the tooth, and it's style of preservation in contrast to the crinoid fragment below it. The rock is a piece of the conglomerate bed I found the large possible bone in. This particular tooth(?) is also interesting because it looks very similar to the second tooth(?) posted from the Devonian site. Potentially from the same species? 

 

I don't know how common it is to find these kinds of fossils in Devonian rocks like this, but this is the first site I've found in Maryland that so readily produces non-Cenozoic fish remains. 

 

If anyone has any ideas what species/genus or even type of fish these are from I'd appreciate any help. 

 

[Fossildude19]

EMP, 

Is the broken edge visible? 

I am not sure this is a tooth, but the circled edge might show whether there is any enamel layer present on it.   

Being it is partial, it may be impossible to ID. 

 

Cropped and Brightened: 

Just not enough detail for me to tell if this is a tooth or not. 

I wouldn't rule it out, but it could also just be a fragment of shell of some sort.    

[EMP]

40 minutes ago, Fossildude19 said:

EMP, 

Is the broken edge visible? 

I am not sure this is a tooth, but the circled edge might show whether there is any enamel layer present on it.   

Being it is partial, it may be impossible to ID. 

 

Cropped and Brightened: 

Just not enough detail for me to tell if this is a tooth or not. 

I wouldn't rule it out, but it could also just be a fragment of shell of some sort.    

 

I can't really get a good picture of the edge, but the fossil is made of a shiny black material with several "grooves" down the length of the piece. The broken edge is visible. It appears to be sort of like a thin ring of the black, shiny material encasing an interior of something grayish. Forgot to add it's roughly conical in shape, tapering towards the broken edge of the specimen. 

 

It is not a brachiopod shell judging by the preservation (the brachiopods in this layer are either white coquina fragments, or internal molds. None are preserved in black like this). 

 

 

[NickG]

Would love to see some of these in person sometime to examine under a microscope.