It's our 150th episode! Wow! This week we're starting our Back To School series with a short primer on stratigraphy. How do archaeologists divide a site into time periods? How did people first figure out that layers of sediment accumulate over time through different processes? How many dirt/soil/sediment puns is Anna capable of making in roughly forty minutes? We'll find out. Links * Stratigraphy: Earth's Geological, Archaeological Layers (ThoughtCo) [https://www.thoughtco.com/stratigraphy-geological-archaeological-layers-172831] * Charles Lyell: Principles of Geology (WGBH) [https://www.pbs.org/wgbh/evolution/library/02/4/l_024_01.html] * About Sir Charles Lyell (University of Edinburgh) [https://www.ed.ac.uk/information-services/library-museum-gallery/cultural-heritage-collections/crc/sir-charles-lyell-collection/about-sir-charles-lyell] * Charles Lyell (Encyclopedia Britannica) [https://www.britannica.com/biography/Charles-Lyell#ref118030] * The Blasphemous Geologist Who Rocked Our Understanding of Earth's Age (Smithsonian) [https://www.smithsonianmag.com/history/father-modern-geology-youve-never-heard-180960203/] * Harris Matrix (Wikipedia) [https://en.wikipedia.org/wiki/Harris_matrix] * The Harris Matrix Tool for Comprehending the Archaeological Past (ThoughtCo) [https://www.thoughtco.com/harris-matrix-archaeological-tool-171240] * How to Read a Munsell Color Chart (Munsell Color) [https://munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/] * Atapuerca (Don's Maps) [https://www.donsmaps.com/atapuerca.html] * Chicken Bones May Be the Legacy of Our Time (Smithsonian) [https://www.smithsonianmag.com/smart-news/chicken-bones-may-be-legacy-our-time-180971027/] Contact * Email the Dirt Podcast: thedirtpodcast@gmail.com ArchPodNet * APN Website: https://www.archpodnet.com [https://www.archpodnet.com/] * APN on Facebook: https://www.facebook.com/archpodnet * APN on Twitter: https://www.twitter.com/archpodnet * APN on Instagram: https://www.instagram.com/archpodnet * Tee Public Store [https://www.teepublic.com/stores/archaeology-podcast-network?ref_id=5724] Affiliates * Wildnote [http://www.wildnoteapp.com/] * TeePublic [https://www.teepublic.com/?ref_id=5724&ref_type=aff] * Timeular [https://timeular.com/ref/chriswebster/]