Monk writes:

I stumbled across this earlier today. Below is the quote and link to
picture.

Although I've seen several areas with similar holes, this particular
set is right next to Bastrop Bayou, near the bridge where CR 227
crosses over it. Approximate lat/long is N29.094 W95.290.

Usually the holes are near a body of water: a river, stream, bayou,
canal, etc. And they are always water filled.

Any ideas?

http://www.texas-flyer.com/LightFlyer/holes.jpg

Sinkholes, areas where the ground at the surface has collapsed downwards due
to underground erosion or subsidence.