Trying to identify this fossil! Found while drilling ~140 ft below land surface in central florida. Just above the limestone

[KellenB]

I'd love some help identifying this fossil! The eggs(?) we found in the same area and depth. My current guess is that it's a fossilized turtle carapace?

 

 

[Meganeura]

The first piece is bone - doesn't look like turtle to me, though I wouldn't rule it out entirely. The "eggs" i'm not sure on. Definitely not eggs - perhaps a burrow, or barnacles though? That would be my guess.

[JohnJ]

Can you gently clean the "eggs" further?

 

@KellenB

[rocket]

remarkable, the "nest", might be one, why not. There are some known, very rare but known.

As mentioned, please clean it and have a close look on it. Perhaps it is broken at some point and you can have a look "inside"

[Meganeura]

3 minutes ago, rocket said:

remarkable, the "nest", might be one, why not. There are some known, very rare but known.

As mentioned, please clean it and have a close look on it. Perhaps it is broken at some point and you can have a look "inside"

That's true - I suppose it could be turtle eggs or gator/croc? Also I guess 140 feet deep may mean we're beyond Miocene?

[KellenB]

18 minutes ago, JohnJ said:

Can you gently clean the "eggs" further?

 

@KellenB

Yes! I'll clean them and post a better picture when I'm able to. I'm overseeing the installation of a monitoring well in the floridan aquifer (hence why we're drilling so deep), and I'm stuck in the field for now

[jpc]

The eggs seem to be of a variety of sizes.  To me that says they are not eggs.   Echinoids, maybe.  Cool find, nonetheless.  

[Sacha]

I wonder if the "eggs" are borehole linings of "colonial" mullusks like Lithophaga or Botula or Gastrochaena. Similar to what I found in the Peace River last year and identified by Roger Portell. (Obviously in much better condition than stream worn.)

[Meganeura]

18 minutes ago, Sacha said:

I wonder if the "eggs" are borehole linings of "colonial" mullusks like Lithophaga or Botula or Gastrochaena. Similar to what I found in the Peace River last year and identified by Roger Portell. (Obviously in much better condition than stream worn.)

This is what I was thinking when I said burrows - I've found similar in the peace, although I've thrown em back so don't really have a comparison piece.

[digit]

We'd likely be down in the Ocala Limestone. Echinoids are exceedingly abundant in this formation. It is old enough that most mollusk shells (gastropods & bivalves) have generally dissolved with the exception of things like pectins (scallops) and oysters which have shells made from a calcitic form of calcium carbonate which is more durable than the aragonitic form that composes the bulk of mollusk species.

 

Cleaning the surface of this grouping with a short soak (like a minute or two) in some distilled vinegar might bring out some of the surface details that would confirm the types of echinoids that are in this cluster.

 

 

Cheers.

 

-Ken

[JohnJ]

53 minutes ago, digit said:

Cleaning the surface of this grouping with a short soak (like a minute or two) in some distilled vinegar might bring out some of the surface details that would confirm the types of echinoids that are in this cluster.

 

Judging from the photo, it would probably be best to start with water to get the mud off.  

[Harry Pristis]

1 hour ago, digit said:

We'd likely be down in the Ocala Limestone

Not necessarily.  The central spine of the Florida peninsula is fossil sand dune of great depth.

[Rockwood]

The bone looks like turtle to me.

[Harry Pristis]

Note how thick some of those siliclastic sediments are:

 

[fossilus]

Another possibility for the "eggs" is a dirty piece of botryoidal agate.

[Sacha]

1 hour ago, Harry Pristis said:

Note how thick some of those siliclastic sediments are:

 

 

 

So Harry, is this sediment on top of the "Moroccan" base of the state and under the subsequent limestone deposition layers?

[Harry Pristis]

1 hour ago, Sacha said:

 

 

So Harry, is this sediment on top of the "Moroccan" base of the state and under the subsequent limestone deposition layers?

No, this is silica sand (siliclasts) overlaying the limestone (Eocene-Oligocene) Ocala Platform.  Origin is primarily from the breakdown of the Appalachian Mtns.  So much time involved!  

[Stingray]

My first impression was chalcedony silica based mineral.

Edited September 12, 2022 by Stingray

[hemipristis]

Top one does look "turtle-y", with the striations/lineations

[Ludwigia]

@KellenB Have you cleaned the "eggs" yet?

[Meganeura]

On 9/8/2022 at 6:21 PM, Harry Pristis said:

No, this is silica sand (siliclasts) overlaying the limestone (Eocene-Oligocene) Ocala Platform.  Origin is primarily from the breakdown of the Appalachian Mtns.  So much time involved!  

is THAT why northern FL gets Oligocene stuff like O. auriculatus at the same time as Megs/Plicoene/Pleistocene stuff, bypassing O. angustidens whereas Central gets Megs and earlier? Cause it's that much closer to the Ocala Platform due to the layers being thin?

[Harry Pristis]

I don't think I can answer your question, Daniel; but, I can refer you to a book.

THE GEOLOGY OF FLORIDA; Ed. by A. Randazzo and Doug Jones.  Mine is a 1997 edition.  Here's one illustration from the book (the abbreviated version -- the detailed version takes up the equivalent of two 8" x 11" pages):

 

 

The book is loaded with illustrations, even fossils, though mostly inverts.  Florida collectors should read this book.

[digit]

I'll second that recommendation--good reading for anybody interested in the geology of Florida. I should re-read my copy again sometime soon to brush-up.

 

 

Cheers.

 

KM

[Meganeura]

Interesting! I’ll definitely see if I can find a copy - gotta add it to my booklist I still really need to get.

[Tahoma]

On 9/8/2022 at 10:00 AM, KellenB said:

 I'm stuck in the field for now

In the drilling business, this could be days, or perhaps weeks