We have a lot going on in this week’s installment of the Geology Flannelcast. Our guest this week is Chris Conwell. Chris is a Ph.D. candidate at THE Ohio State University and he studies ancient glacial activity on Earth nearly 450 million years ago. Also, Ryan Thornburg (Jesse’s brother) stops by and we determine once and for all if Jesse and Ryan really didn’t go swimming for a whole summer in 1992 because it was too cold due to the eruption of Mt. Pinatubo in 1991. And if that wasn’t enough… we also cover a huge tanzanite discovery and the end Permian extinction event.