Cerro Gordo Fossil Finds

[minnbuckeye]

As I traveled from Minnesota to Morrison Iowa for a mineral/fossil presentation that our rock club was involved in, I had a few hours to venture off course and visit Bird Hill in Floyd County. The exposure provides fossils from the Cerro Gordo, Lime Creek, Devonian Period. If anyone has visited the Rockford Tile and Brick Quarry, the same strata is exposed at both sites. The Cerro Gordo is brachiopod rich with 40 known species. In my short visit, 15 species of brachiopods were found and HOPEFULLY identified correctly! I do have a bag of brachiopods that I am still trying to work through. So hopefully my count will increase with time. Here are a sampling of the variety the Cerro Gordo provides. 

 

 

  

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

Edited September 23, 2021 by minnbuckeye

[Jeffrey P]

Congrats. That's a lot of really nice brachiopods for a few hours of collecting. And different species than we see here in New York's Devonian though many of the genera are the same.  Hope to check that place out some day. 

[ricardo]

  congrats!

[tombk]

Beautiful collection! One interesting thing that I noticed when I collected in that formation (at the Rockford Fossil Prairie Park) was that most of the brachiopods I found had both valves intact, except for the Sulcatostrophia camerata, which I found only single valves of. It looks like you had the same experience. I’m not sure what accounts for that. 

[Crusty_Crab]

1 hour ago, tombk said:

Beautiful collection! One interesting thing that I noticed when I collected in that formation (at the Rockford Fossil Prairie Park) was that most of the brachiopods I found had both valves intact, except for the Sulcatostrophia camerata, which I found only single valves of. It looks like you had the same experience. I’m not sure what accounts for that. 

I believe they are concavo-convex brachiopods, which means the ventral (pedicle) valve is concave and the dorsal (brachial) valve is convex. The view on the left would be the pedicle valves and the view on the right would be of the brachial valves. I have found individual valves, for example this is Schizophoria iowensis (Hall, 1858) with the muscle attachment scars visible in the interior of the pedicle valve:

 

 

Edited September 23, 2021 by Crusty_Crab

[tombk]

47 minutes ago, Crusty_Crab said:

have found individual valves, for example this is Schizophoria iowensis (Hall, 1858) with the muscle attachment scars visible in the interior of the pedicle valve:

Nice!

[Paleorunner]

Wow, what a nice collection of brachiopods. 

[ClearLake]

Very nice group of brachiopods, Mike. I remember looking that site up last summer, but not going to it. I’ll have to put it on my list. 

[fossilhunter21]

Nice finds! Congrats!

[minnbuckeye]

8 hours ago, ClearLake said:

I remember looking that site up last summer, but not going to it.

@ClearLake, bring knee pads to bird hill. Most of the time I crawled around on the ground and it took a toll on my knees. By the way, I left MANY fossils behind, just so you would have something to find!!

[RJB]

  Hey Mike, Im not a brachiopod guy but some of those are quite nice. 

 

RB

[Tidgy's Dad]

I missed this. Probably because it was posted on the day after my birthday. Which lasts several days.

Some really beautiful fossils found, Mike, I think the preservation in some of the various Ordovician units in the USA is quite remarkable. Considering the fragility of some of the specimens,, it's amazing they've been preserved at all, but the detail visible is astounding. 

This thread will also now prove very useful to me. 

Thank you, 

[FossilDAWG]

They are indeed beautiful specimens, but they are Devonian not Ordovician.

 

Don

[Jeffrey P]

On 9/23/2021 at 7:47 AM, minnbuckeye said:

As I traveled from Minnesota to Morrison Iowa for a mineral/fossil presentation that our rock club was involved in, I had a few hours to venture off course and visit Bird Hill in Floyd County. The exposure provides fossils from the Cerro Gordo, Lime Creek, Devonian Period. If anyone has visited the Rockford Tile and Brick Quarry, the same strata is exposed at both sites. The Cerro Gordo is brachiopod rich with 40 known species. In my short visit, 15 species of brachiopods were found and HOPEFULLY identified correctly! I do have a bag of brachiopods that I am still trying to work through. So hopefully my count will increase with time. Here are a sampling of the variety the Cerro Gordo provides. 

 

 

  

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This is very timely. I was just at Rockford Fossil & Prairie Park three weeks ago and picked up many, many specimens and I'm still working on IDing them. Thanks a bunch. This post has helped e and I'm sure will help others who visit these Cerro Gordo sites. 

  

 

 

 

 

[Misha]

I also missed this when it was first posted, some absolutely gorgeous brachiopods!

[Denis Arcand]

Lovely find