Crinoid? How is this possible?

[JenEvans]

Hi all! First post. 

I found these in my backyard, different spots, months apart, near Keller, TX.

I've hesitated to post because I feel like this can't be possible and I must be missing something obvious as a novice fossil hunter. 

 

The rock in first 3 images was found 2/3 buried, including the part with the... leaves?

It was getting dark, so I thought a leaf had stuck to it somehow. I tried scraping it against something to knock it off... then tried to pull it. When it didn't budge, I decided I'd deal with it inside.

 First pic is front after it had dried and had some dirt brushed off about a week later. Second is the back side, dried out. Third is front, just after bringing it inside. 

(Edited to correct descriptions. I somehow uploaded in reverse)

 

The other one, in last 2 pics, was also found partially buried in my backyard, but many months ago and I can't remember specifics of depth. I'm always digging something up lol. 

Any ideas? 

Edited September 10, 2022 by JenEvans
correct image descriptions

[daves64]

Looks like plastic sheeting embedded in concrete of some sort.

[JenEvans]

20 minutes ago, daves64 said:

Looks like plastic sheeting embedded in concrete of some sort.

I considered that, but what do you make of the shape and patterns on it... or where it appears to root into rock (3rd pic)?

Any thoughts on second rock?

[Ludwigia]

I'd agree that we're looking at concrete in both cases.

[digit]

Yup. The composition of the material suggests concrete--cement with pebbles mixed in. It is not unheard of to use something like plastic sheeting to contain concrete while pouring it for steps, sidewalks or foundations. Quite possibly from some older construction on the property from a previous owner.

 

 

Cheers.

 

-Ken