Oyster bed in Mancos Shale at Gallup Hogback

[kgbudge]

I took a geology excursion a couple of weeks ago, and had the chance to explore the I-40 road cut through the Gallup Hogback east of Gallup, New Mexico. Rather to my surprise,  I came across a nice oyster horizon within the Mancos Shale.

 

I realize the preservation is sketchy enough to make precise identification difficult. I'm wondering if these might be "baby" Inoceramus. I'll try to post some better pictures of samples I brought home later.

 

And, since I consider myself lucky if I even get the right phylum -- I suppose another possibility is ostracods.

[FranzBernhard]

5 hours ago, kgbudge said:

I'll try to post some better pictures of samples I brought home later.

Yes, please!
Franz Bernhard

[kgbudge]

[kgbudge]

[FranzBernhard]

Thanks!
Any chance for some measurements ?

At the moment, I am in the bivalve camp.
Franz Bernhard

[kgbudge]

Typical maximum size across an individual is about 8mm. The symmetry does suggest bivalves. Well-sorted bivalves, so to speak, so as I think about it I'm inclined to think these are adults of whatever species they are.

 

Setting is a thin shaly limestone bed (by thin I mean less than 2 cm) in what is otherwise a thick sequence of gray shale.The stratigraphy puts the fossils are on the top side of the bed.

[FranzBernhard]

Thank you!

Now we need some Manco shale experts! @JohnJ, @DPS Ammonite are you able to help? Thank you!
Franz Bernhard

[JohnJ]

@PFOOLEY. 

[DPS Ammonite]

We need some clearer photos of just a few of the best shells. I suspect they may be similar to forms found in Texas and may be IDed by some our Texas experts.

[Jared C]

Looks very reminiscent of the shell hash in the Eagle Ford here. A USGS description of the formation implies that there are abundant pelecypods, and I assume they're referring to the hash with that. Perhaps that narrows it down

[kgbudge]

20 hours ago, DPS Ammonite said:

We need some clearer photos of just a few of the best shells. I suspect they may be similar to forms found in Texas and may be IDed by some our Texas experts.

Unfortunately, I simply don't have the camera equipment to easily do better. But I'll work at it a little and see what I can do.

[DPS Ammonite]

9 minutes ago, kgbudge said:

Unfortunately, I simply don't have the camera equipment to easily do better. But I'll work at it a little and see what I can do.

Have you tried to put a hand lens/loupe in front of a phone camera lens to take a picture?

[PFOOLEY]

Maybe compare to the genus Nuculana...and Cardium...I've seen those in the Mancos.