Does the data set describe conditions during a particular time period?
Beginning_Date: 1930Ending_Date: 1998Currentness_Reference: Time period of information content for geologic data in the Yucaipa database reflects (1) the vintage (1930, 1938, 1952, 1966, 1975) of archival aerial photographs used to interpret geologic features and (2) ground observations made by the map authors between 1977 and 1998.
