GEOLEX database Geologic Unit: Andover Usage: Andover Granite (MA*) Age: Ordovician* Silurian* Geologic Province: New England province* Areal Extent: MA* Type Locality: Type area: occupies large area around Andover, Essex Co., northeastern MA (Clapp, 1910). Unit Name History: Named (Clapp, 1910). Overview (Emerson, 1917). Age modified (Goldsmith, 1980). Age modified; Isotopic dating (Goldsmith and others, 1982). MA State Geol. Map usage (Zen and others, 1983). Overview; Age modified; Isotopic dating (Wones and Goldsmith, 1991). Isotopic dating (Hepburn and others, 1993). Note: If you need more information, please contact Nancy Stamm (nstamm@usgs.gov). Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys. "No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses (). Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]). U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA URL http://ngmdb.usgs.gov/ngmdb/ngm_catalog.ora.html Database project personnel Last modified: 7-Jan-2007