"Note: Corona has just contracted to put in a complete Sewer System embracing eleven miles of sewers; also over $100,000.00 in Street improvements." See also HEH 356004 for an earlier map of Corona, and HEH ephMPCALIF0019 for a copy of this map. An MS note on this map suggests the 1909 date for this map. MS notes: 1909 356005. Prime meridian: GM. Relief: hachures. Graphic Scale: Chains. Projection: Plane. Printing Process: Lithography.