Strange rock/fossil found in southern Missouri with indented triangular patterns

[ericabelle]

Hello! I found this rock in the empty lot across the street from my house in southern Missouri (Howell County). This rock is approximately 6 inches long (15cm), and it seems very heavy for its size. I thought this rock was just another weathered rock until I noticed the indented pattern. Then I wasn't so sure.  Stainless steel doesn't scratch it, and a magnet isn't attracted to it.  I find a lot of crinoid stems and little gastropod fossils, along with colorful chert,  in my own backyard, but it's a whole different world on top of a tall hill across the street from me. I find lots of smooth weathered rocks, and rocks that look "melted" (freeform shapes). Often there are only 2-3 of each of these strange rocks. Most of the rocks there are white and grey chert.

Well, that may be too much information, or not enough - this is my first post here. Hopefully my three photos load...

Thanks in advance for any ideas you might have! =)

 

Edited May 8, 2021 by ericabelle
Photo adjustment

[Kane]

Try reuploading them as JPG as the forum cannot translate the .heic file format.  

[ericabelle]

Ok, thank you - I'll try that!

[Anna Marie]

[Tetradium]

On 5/8/2021 at 12:11 PM, ericabelle said:

Hello! I found this rock in the empty lot across the street from my house in southern Missouri (Howell County). This rock is approximately 6 inches long (15cm), and it seems very heavy for its size. I thought this rock was just another weathered rock until I noticed the indented pattern. Then I wasn't so sure.  Stainless steel doesn't scratch it, and a magnet isn't attracted to it.  I find a lot of crinoid stems and little gastropod fossils, along with colorful chert,  in my own backyard, but it's a whole different world on top of a tall hill across the street from me. I find lots of smooth weathered rocks, and rocks that look "melted" (freeform shapes). Often there are only 2-3 of each of these strange rocks. Most of the rocks there are white and grey chert.

Well, that may be too much information, or not enough - this is my first post here. Hopefully my three photos load...

Thanks in advance for any ideas you might have! =)

 

classic chert with top, etc. But the indents are weird enough. Could be stromalites? 

[ericabelle]

I hadn't thought of stromalites - I always thought of their designs as mostly circular; but I did find some more linear patterned examples online.  So I'm sure it's possible!

[Fossildude19]

Stromatolite is a possibility. 

 

@FossilDAWG   @TqB

[FossilDAWG]

1 hour ago, Fossildude19 said:

Stromatolite is a possibility. 

 

@FossilDAWG   @TqB

Maybe, but I'm getting more of a geological vibe.  A polished section might be necessary to be certain.

 

Don

[ericabelle]

On 5/10/2021 at 10:15 AM, FossilDAWG said:

Maybe, but I'm getting more of a geological vibe.  A polished section might be necessary to be certain.

 

Don

Well, that would track - I'm always saying that I go out hunting for fossils and find pretty or interesting rocks instead!  I'll post it to a Rock ID forum and see what everyone thinks.Thanks!

[ericabelle]

UPDATE: I posted this rock on a Rock ID forum, and there were guesses of bone, an indian maul, and a rock from the Bermuda Triangle.  The most likely suggestion was that the gray is a hard material like chert alternating in layers with a softer material. The softer material dried and cracked, and a harder material entered the cracks, and the weird indentations were set.  Weathering occurred, and made the undercut, layered rock!  That seems probable!