This textbook has been adapted from existing open-source text books: An Introduction to Geology from Salt Lake Community College, Introduction to Earth Science from Laura Neser, Physical Geology from ...This textbook has been adapted from existing open-source text books: An Introduction to Geology from Salt Lake Community College, Introduction to Earth Science from Laura Neser, Physical Geology from BCcampus, High School Earth Science by Wikibooks, as well as various other sources.