Mountain Biking?

First off I have to address a previous post about me getting elbowed. Somebody wrote in a comment that it is actually safer for the rider to use an elbow than to take their hand off their bars. Point taken.
I haven't riden in a week and wasn't able to go to Mattesen last night. I wanted to go on the road, but Damon invited me to the trails in Palos. All I have is my cross bike but he goes out there all the time with his so I went. I asked him if a pair of 700 by 30 tires would be fine. He said they would but I soon found out I would have appreciated something a whole lot beefer under me. We met up with a friend of his who had a mountain bike. As soon as we got into the parking lot there was a guy sitting in his car with the door open with blood trailing down from his knee. Not a good omen.
All I could say is that is probably my last time on those trails. For me it is hard enough to stay upright on the street without obstacles. Now throw in roots and rocks. Needless to say my forearms got a workout trying to keep my hands on the hoods while breaking.
I would say we were not even 100 yards into the trails and I fell. I slid off of something that looked like concrete at a 45 degree angle but was actually made of packed dirt. Hurray for me! I have another hour and a half of this. The good thing is I didn't fall again. Not for a lack of trying mind you. Just the sheer will of God looking down on me kept me upright some of the times.
So what did I learn? Don't go to Palos with anything less than a mountain bike if you don't have any skills. The only good thing about having a cross bike out there was I was able to ride home from the forest preserves at a good pace.