We recently signed up for the public tour of the Canyon Lake Gorge. This gorge did not exist before 2002. It was caused by a flood when the dam got too full. Canyon Lake dam is an earthen dam. The spillway is to the left of the dam when standing facing the structure. We saw part of the gorge from the top when we walked around the dam area. We could see the bottom part when you drive on Access Road.
It was very exciting to find that they do tours. You have to visit their website at https://canyongorge.org/tour. The tour costs $10. The tour lasts approximately three hours. There is one guide and two docents who make sure folks stay in the proper areas. Susan James was our tour guide. She was a wealth of information. Every time I just thought a question she answered it before I could raise my hand.
The dam was built in the late 1950s. It had never needed the spillway before the 2002 flood. What was unearthed was quite amazing. We got to see what might be dinosaur tracks.
Tracks that may or may not be a 4 legged dinosaur. 
This is be a two legged dinosaur
We also got to see many fossils. You make look at and touch while on the tour. But that is it. You may not take anything with you. This is government property making this theft a felony.
Part of the aquifer is exposed before is goes back under water. It had rained earlier in the week so we walked through water to see beautiful falls.
This was also my first exposure to a fault line. It was visible to see that two sides pushing/pulling against each other. It is a true wonder.
Even though it was in the high 30s when we started the tour, it was a great time. Note this is rocky hike. You don’t move fast but the path is not handicap accessible. I recommend good, weatherproof hiking boots for this adventure. You will be walking on rock, mud and through water at times.