Coral?, dunno....dunno.

[Benjaminpb]

I found these in a local  Austin creek.

I think one is coral but I'm not sure what the other two are. Any ideas?

[Ludwigia]

The first 2 appear to be geological. The 3rd is either a bivalve or a gastropod.

[Fossildude19]

Cropped and brightened:

 

 

 

 

 

I agree with Roger's assessment.

[abyssunder]

The third one could be a weathered echinoid.

[Benjaminpb]

Thank you 

[Doctor Mud]

The first image reminds me of pumice or some other vesicular volcanic rock.

Does it float?

[Rockwood]

I suspect the second one may be pyrite, the center being where a larger crystal has weathered away.

[abyssunder]

I think the first item is an ichnofossil called Entobia.

 

" Typically a pebble or shell that has been affected by this kind of sponge infestation will have a series of regular-shaped circular holes on the surface. These holes may cover the entire surface of the object in severe infestation. Sometimes there are only a few holes when the sponge is just starting to colonise the pebble. These may appear as a single row of holes with a range of increasing size. There may be inter-connected surface lines or grooves which look like the impressions of rows of beads.

Below the surface, deeper down inside the pebble, the sponge creates a fairly hap-hazard network of spaces that resembles bubbles or an irregular sort of honeycomb. This inner damage is revealed when the outer surface of a badly sponge-infested pebble is either broken or worn away. " - Jessica Winder