I rotate science units monthly and this is the start to our rock, fossils, and volcano unit which will take a couple months to go through. If you have seen my other science units you know I am a huge collector of all things natural. A tray of crystals with a page from some workbook to sort them by size. I try to add a paper work to most things because my kids love to do a paper element to take home. Petrified wood to handle. Naming different rocks. I collected the geodes with the red dots and rubber bands to hold them shut in a stream in Iowa - a fossil meca. When I taught Montessori in Iowa City, fossils were at every stream and mixed in the gravel in neighborhood driveways. I could actually walk down the street and collect fossils in people's drive. I will post my fossil unit later on. Watch for it. http://www.rocksforkids.com/ http://geology.com/rocks/