This was too cool (in my opinion) to not share. It might be geared for “grades 6-12,” but this digital journey and lesson is pretty neat regardless of your age and whether you have been to these sites or not. In any case, it includes a virtual tour of columnar jointing in California, and images from similar sites in Iceland, and second site in California. New to me, but perhaps I should have known, there is a scientific technique used by various “ologists” to study lichens as a means to determine the age of rocks, lichenometry. take the tour
By Man vyi – Own work (own photo), Public Domain, Link