Running time 2 hours This episode is the fourth monthly package in the History of the Earth Calendar. It combines the daily episodes for April 2014, covering the Silurian Period of the Paleozoic Era. As usual, I've left the references to specific dates in the podcast so that you can, if you want, go to the specific blog post that has links and illustrations for that episode. They are all indexed on the right-hand side of the blog. As the year continues, there will be occasional new episodes in addition to these monthly assemblies. If you have questions or comments, please let me know, either here on the blog – see the tab page for Questions, above – or contact me by email at rigibson at earthlink.net. I’ll try to respond. You can of course also leave a review on iTunes. I really do appreciate your feedback. Thanks for your interest and support. —Richard I. Gibson