I made several mistakes. First, I did get out and recon, and I picked a route. That's where my brain stopped working. I got into the truck and then proceeded to drive a different route. Bad idea.
I didn't stop when I heard (and felt) the truck run up onto a boulder. I should have stopped because that was not part of the plan. I kept going forward. Bad idea.
I was turning around in a wash along a BLM route east of Barstow. There was one, and only one, huge boulder nearby and I managed to run right over it. It's about the size of a 2 yo sitting cross legged in the sand. OK, that's a bit of exaggeration, but just barely. You can see it in these photos.
You can see from my tire tracks that the boulder went down one side of the truck, so it didn't hit the transfer case and I have more ground clearance along that line. Not enough though.
After hitting the rock, I should have waited for the truck to sense it was high-centered and automatically raise the suspension higher. Then I could have raised it even higher after that. But I forgot all that and just kept driving until I was free of the thing.
I was very worried that I might have done some serious damage and might be leaking some vital fluid. There weren't any signs of leaks, but I didn't take any chances. I changed my plans and took the shortest trail back to civilization.
Luckily, there was no serious damage. In the end, I was saved by the factory skid plates under the Land Rover. Without that, the gas tank would have been ruptured or ripped out. Here's a photo showing the underside of the truck. You can see the longitudinal indentation in the skid plate that covers the gas tank as well as the dent in the lateral frame member.
For the record, here is a google map centered on the location of my mishap. I was driving a natural gas pipeline service road that is also a BLM open route. Sometimes I drive these roads as an alternative to the highway. Why? Because I can. Plus, I often come across interesting things and wildlife out there.
You can see that the map is not centered on the marked route (google maps shows much of the route I was driving). I got lost and had started south in that wash. After getting out and walking around, I decided that I was going the wrong direction and I was turning around to return to the trail. I hit the boulder while turning around.