I just remembered that, while I was out near Mounds Reef looking for a dashpoint today, I left some rocks behind that I'd planned on bringing home. They were chunks of what looked like a huge geode (about one foot in diameter) that had broken up. Some of the chunks were really big, with part of the spherical surface on the outside and a lot of crystalline rock on the inside (or what used to be the inside). Many of them fit together so you could get an idea of the original size. I had to drive through the bottom of a dry streambed for half a mile to get to the area, but it didn't really start raining today until after I'd left, so I'll probably have to go back after it's dried out a bit. It's funny that this isn't the first time I've left some rocks behind and had to go back to pick them up, but it's always been worth it to return.