The museums of Philadelphia are noted for both their variety and their longevity. Some of these institutions have been present since before the American Revolution and reflect the continuity within a population for which education was always a predominant goal. Others have arisen over subsequent centuries in response to various needs. Some, such as the American Philosophical Society and the Fairmont Water Works, are eighteenth-century institutions that relatively lately acquired a more formal museum format. Colonial interest in natural history, mineralogy, and natural resources with collateral maps and papers makes them a prime resource for historians of geology. All of these institutions reflect the nature of the museum movement itself from often private or privileged collections to those both welcoming the public and serving as sturdy arms of education. Historians of geology will find maps, instruments, collections, books, and personal and government papers that are of much interest.