Fossil Weevil from the Green River formation

Insects from the Green River formation can be difficult to ID down to a species, let alone a generic level. Often you are trying to compare a 2D fossil to 3D pictures of extant insects and all you can do is hope you are correct.  Below is a specimen I purchased because of the good preservation, but also because it had been ID'ed as a Weevil already.  I need to go through my own findings to confirm but I think I have found examples of this same kind of insect on my collecting trips.

I am still trying to find some good resources that list known insect genera from the Green River formation but they are hard to find or expensive to purchase.  At this point I can only say that this fossil is of a member of the Superfamily  Curculionidaea.

A low light shot of the fossil shows some nice details

A direct light shot shows the true color of the fossil better.

This fossil was found in the Parachute Creek shale member of the Green River formation, in Rio Blanco County, Colorado. The Green River formation is dated to the Eocene period, Lutetian stage (about 46 mya).

Check out an older post of mine where I discuss the geology of the Eocene lakes that once existed in SW Wyoming and NW Colorado.

In another one I posted some of my exceptional finds from Douglass Pass.

Eurypterus lacustris from the Bertie formation

This past fall I finally found some Eurypterid fossils while visiting the Ridgemont Quarry near Stevensville, Ontario, Canada. It was my fourth or fifth trip to the quarry and previously I'd only found isolated parts of the animal. None were 100% complete but all were more than I had ever found. At the quarry the fossils are found by splitting thin bedded dolostone. The beds formed in a lagoon like habitat that was shallow and low in oxygen. Because the rock is dolomite this can be taken as evidence that the paleoenvironment was very warm with rapid evaporation. This is further reinforced by layers that have mud cracks preserved. Most of the fossils of Eurypterids that are found are molts of their exoskeleton. Depending on how quickly they became buried they would often break apart into smaller individual segments and be scattered by the currents. Thus to find any specimens of whole or nearly whole bodies is rare.

Here is the pit I was working

My finds as I had them set aside before I wrapped them up

Specimen #1 is a positive and negative of the same fossil that is just the front half of the animal. Note that the lower plate is two smaller pieces that I glued back together. This is not uncommon at the site as the dolostone is very fragmented in places with cracks from previous blasting (it is an active quarry after all).

Specimen #2 is mostly intact but has many bits and pieces scattered about. The exoskeleton may have started to disintegrate just before it was buired or the pieces are from a different exoskeleton.

Specimen #3 is the most intact with nearly the entire Teslon (the spiny tail bit) and one of the swimming arms. I have no idea what happened to the upper half of the other side. I must have lost it among the rock debris during excavation and was not able to find it.

Long Pause

It's been a while since I posted anything to my blog and I apologize to my regular readers for that. This summer I was getting some work done on my house which distracted me and took away my usual backdrop for photography (the brick wall on the back of my house). It also forced me to box up all of my fossils and put them into storage since the space was needed for the contractors to work in. Additional stress came from my day job in the form of several projects that I fell behind on and had to play catch up.

The good news is that my renovations are complete and I'm caught up with the day job. In the next few weeks I will be moving my fossils into a new, larger work space and I'll be working to sort them and find new material to write about. I didn't get a summer vacation this year but hopefully I can sneak some small trips in before winter gets too cold.

In the meantime here are some pictures of finds from this spring that don't really need full blog entries:

Phacops rana molts from the Moscow Formation at the Penn Dixie site in Blasdell, NY.

The base plates and stem attachment point of an Arthrocantha sp. Crinoid from the Moscow Formation at the Penn Dixie site in Blasdell, NY.

And a small geode formed by a fossil that contains small Calcite crystals and some blades of what I think are Barite that I found in a piece of the Tichenor Limestone (bottommost layer of of the Moscow formation) along the shoreline of Lake Erie.

That's all for now, I'll hopefully be back to regular updates in the coming weeks. Thanks for stopping by!

-Dave

Eurypterids from the Ukraine

I'm cleaning out a folder of pictures this week. Below are pictures of three Eurypterid fossils from the Ukraine. They are likely Balteurypterus tetragonopthalmus as that seems to be the most common species that I see available on in the Internet. They come from near the River Smotrych in the Kamianets-Podilskyi region of Khmelnytskyi Oblast, Ukraine. The age is late Siilurian (Pridoli stage).

This is the most complete specimen and the smallest. It's just a spall off of a larger piece of Dolostone.

This is what it looks like when put back into place.

The next fossil is a bit larger but more incomplete.

The last specimen is very fragmented and has been patched back together from several smaller pieces.

The rock in which these fossils are preserved is very similar to that which is found in New York and Ontario that are part of the Bertie group. A yellow-tan, fine grained dolostone which is interpreted to represent sabka (salt flat) type environments where a shallow lagoon is host to hyper-saline water due to higher evaporation rates than can be refreshed by the ocean during high tides. These kind of environments are found today in the Persian Gulf region. A theory posits that the Eurypterids would migrate to the lagoon to molt since the hyper-saline water would prevent predators from following and preying on the arthropods while their new exoskeletons hardened.

Anataphrus vigilans from the Maquoketa formation

I'm hoping to get out to the Midwest this spring and collect the Maquoketa formation for myself but until then I get lots of nice specimens from Tim on E-bay. I bought this nice enrolled specimen of Anataphrus vigilans (from Eldorado, Iowa) from him not too long ago.

The Maquoketa formation is late Ordovician in ageand roughly corresponds to the Richmondian stage (Hirnantian stage of the ICS). This makes it a good comparison to the similarly aged fossils found near Cincinnati and northern Kentucky.

A couple of Decapods from the Brittion Fm. of Texas

Decapods is another name for crabs and their kin. Here I have two partial crab fossils from the Britton formation (Cretaceous, Turonian stage) of Texas.

The first fossil is Cenomanicarcinus vaelstrani from near Little Elm

The second fossil is a Notopocorystes dichious from near Las Colinas

I received both specimens from an auction that I won on the Fossil Forum site. Thanks to Travis for sending me these crab fossils.

Crinoid roots and Calymene Trilobites from the Waldron formation

I've been showing off alot of fossils that I purchased recently and this is one of my favorites. It's a pair of Crinoid holdfasts or "roots" which has a pair of Calymene trilobites huddled underneath. It comes from the Waldron shale on Indiana which is Silurian (Sheinwoodian to Homerian stage) in age.

Here you can see the two holdfasts looking like stumps in a freshly cut forest.

Underneath the larger of the two holdfasts are the Trilobites.

They are both complete and fully articulated

This specimen was found by Mark Palatas from whom I purchased it.  I was fortunate enough to see some of his collection and his prepping work station when I visited his home a few months ago. This specimen, however, was not prepped by Mark but by one of his friends.

Dendrophyllia and Dromiopsis from Denmark

Dendrophyllia candelabrum is a very odd looking coral. It's known from Paleocene age rocks in Europe but is primarily found in the Danish basin and notably at exposures near Faxe, Denmark. It's a scleractinian coral but has a very dendritic growth pattern of loose, tube like shapes. They formed reef mounds in deeper, colder areas of water within the basin.

Sometimes there are decapod fossils among the coral branches. Below is a carapace from a Dromiopsis rugosa crab. This is typically how this species is found and rarely are they articulated.

The specimens shown above came from the seashore near Faxe, Denmark and are from the Paleocene (Danian stage). Thanks to Christian for sending me these specimens!

Protocallinassa sp. claw from the Navesink formation

As a companion piece to the Ophiomorpha nodosa burrows I posted last week, here is a partial claw from the arthropod that lived in the burrows. It's called Protocallinassa and was a ghost shrimp that lived on the seafloor scavenging for food. It's not too commonly found as the exoskeletons often fell apart in the water current after death.

I found this fossil at Big Brook near Marlboro, Monmouth County, NJ. It probably came from the Navesink formation (Cretaceous, Masstrichtian stage)which lines the banks of the creek.