OMG! These things are crazy expensive. Is it worth it to pay $200+ for a timeline? For us, I decided that it was definitely not worth the money for a rising sixth grader who will probably spend two weeks with Lesson 2 this summer. While we plan to visit the grand scheme of things again in the fall, it will be through Big History Project and not Montessori Great Lessons. The coming of life on earth will be the same, so a timeline would be nice. I would definitely pay $50 for a 2'x10' poster that covered the Paleozoic, Mesozoic, and Cenozoic, but any more than that kind of makes me cough. I would even have paid $80 for a 2'x10' timeline poster that came with a blank 2'x10' poster and digital download cut outs to place on the blank one. I would have seriously considered $100 if it came with all of the previously mentioned items and some nice extras that go along with Lesson 2, even if the extras were just digital downloads. However, I cannot bring myself to pay over $200 for a timeline, blank, and pieces that will be used for two weeks. So, after I finished ranting about the cost, I went to the Parent-Teacher Store and purchased a 2'x12' roll of bulletin board paper for <$4 with tax and got to work. I figured a scale of 1"/ 5 million years and marked off periods including the Ediacaran from the Proterozoic Eon. I purchased the timeline mute images for $6 from Garden of Francis and started coloring. I printed paleogeographic images from the Paleomap Project. I printed information about the big five mass extinction events from BBC Nature.I also used information from BBC Nature's Geological Time Periods. I used information from all over the place including BBC about ice ages. I researched trilobites, sea lilies, insects, amphibians, and early reptiles to try to get a handle on general times of diversification and extinction. I thought this article about the complete hexapod fossil helpful/ interesting. You can see my little blue hexapod running out of the Devonian period and into the Carboniferous. It may not be completely accurate scientifically, but, as Miss Barbara pointed out, this is an impressionistic introduction, but I do hope the few things I researched are close to current scientific understanding! Unfortunately, the images of dinosaurs from the Garden of Francis mutes are too few and too old school inaccurate to use for my Mesozoic section so more research is ahead for this next week!