Canyoneering in Texas?

Anyone know of any technical canyoneering in Texas? I've heard Big Bend State and National Parks have some canyons, but I don't know more beyond that.

Any slot canyons with solid rock in Palo Duro Canyon or Caprock Canyon State Parks?

WOW, Palo Duro Canyon.
I havent thought about that place in a long time. I started climbing there about 17 years ago. There is hardly any solid rock, but we found enough....I was even leading on gear on some of that kitty litter back in the day.
Never heard of any slots though....