http://book.klll.cc/ebooks/subject/36621.opds 2025-11-18T22:58:03Z Books about Geology -- Illinois -- Maps Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-11-18T22:58:03Z https://book.klll.cc/ebooks/65704.opds Guide to the Geologic Map of Illinois Illinois State Geological Survey