Museum Of The Earth Field Trip: Geer Road Quarry

[MarleysGh0st]

Today was first of the Museum of the Earth's summer field trips, to the Geer Road Quarry, outside of Hamilton, NY (Middle Devonian, Moscow formation). This is a great location for newcomers to try, because it's hard picking up a rock without a fossil in it!

I collected a sampling of brachiopods and bivalves, but my prizes of the day were these two partial specimens of Dipleura dekayi, a large pygidium and a smaller cephalon:

The matrix of the second specimen had other fossils as well, including this curious one, a crushed straight cephalopod (?) with concentric lines on its shell:

I also found some Greenops trilobites, mostly just pygidiums, but this specimen appears to still be intact, although the cephalon is bent forward. Some prep work is needed to see what's really there!

A beautiful, sunny day for some productive collecting!

[Fossildude19]

Great finds, Marley's Ghost!

Thanks for posting them.

Your straight cephalopod looks quite like mine, pictured HERE, which was identified by Dave (shamalama) as a Bactrites aciculum.

Good luck with the prep on the Greenops - please post results here!

Regards,

Edited June 18, 2013 by Fossildude19

[KansasFossilHunter]

Sweet!

[MarleysGh0st]

Your straight cephalopod looks quite like mine, pictured HERE, which was identified by Dave (shamalama) as a Bactrides aciculum.

Thanks for suggesting this identification! I'll have to put researching Bactrites on my list of things to do. The Paleobiology Database lists several species of this genus, but not B. aciculum. And I know nothing about the differences between all these!

[lissa318]

Looks and sounds like a great trip!!!

[GerryK]

MarleysGhost

I would like to pass on some interesting information about the Geer Road Quarry. The shales exposed at this locality are from the Moscow Formation but not from the Windom or Kashong Members but from an undescribed interval between them according to work done by Dr. Carl Brett. The other interesting thing is this interval is the only section in the Hamilton Shales where I have found Greenops boothi. The Greenops from this locality is the same as the Neotype of Greenops boothi from Pennsylvania.

[MarleysGh0st]

Thanks for that info, Gerry.

[Shamalama]

Nice finds, Marleyghost. I sure hope the Greenops comes out intact!

[MarleysGh0st]

There was a request for photos of the Greenops specimen, after I finished my prep work. The prep came out very nicely; getting decent photos of the specimen was harder. After trying twice in direct sunlight, I finally tried taking photos outside on an overcast day. That wasn't perfect, but it'll do.

This was the side that was exposed when I collected the sample. There's some damage to the cephalon on this side.

Here's the side was that buried in the matrix. I saved the counterpart, where some detail of the left eye is visible.

And here are two dorsal views. A small brachiopod was uncovered from the matrix near the left side of the pygidium, as a bonus.

One mistake I made with the prep: I tried protecting the specimen with a coating of Paraloid B-72, but the mixture was too thick and the result looked like a gummy mess, so I washed it off with some acetone. There's some discoloration on the cephalon, which may be a remnant of that coating.

Edit: "Thick" not "think".

Edited July 15, 2013 by MarleysGh0st

[crinoid1]

Looks like a great trip! I'm loving the Dipleura trilo pieces.

One mistake I made with the prep: I tried protecting the specimen with a coating of Paraloid B-72, but the mixture was too think and the result looked like a gummy mess, so I washed it off with some acetone. There's some discoloration on the cephalon, which may be a remnant of that coating.

I have done much worse than that! I found one of my nicest specimens of a crinoid called Allocatillocrinus when I was 10 or so. I got real scared that I would bust it up on the way home, so I doused it in superglue. What a mistake! It will never ever come off.....