GEOLEX database Geologic Unit: Greenleaf Mountain Usage: Greenleaf Mountain Formation (MA*) Age: Precambrian* Proterozoic, Late* Geologic Province: New England province* Areal Extent: MA* Type Locality: Greenleaf Mountain near northern boundary of Lexington quadrangle, Middlesex Co., northeastern MA (Bell and Alvord, 1976). Unit Name History: Named (Bell and Alvord, 1976). Age modified (Goldsmith, 1980). Not used (Zen and others, 1983; Goldsmith, 1991). 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