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National Geologic Map Database

Since the late 1800's, the U.S. Geological Survey has been responsible for maintaining a lexicon of geologic names for the Nation. The published lexicons (see below) include brief definitions for each unit (e.g., the lithology, thickness, age, underlying and overlying formations, and type locality). These were published at irregular intervals.

Copies of these USGS publications are provided below, for quick reference. [For downloadable files exceeding 10 MB, the filesize is noted.] Statewide and regional correlation charts, lexicons, and other stratigraphic resources are provided here.

Lexicons
Years addressed by publication Description USGS Publication
1902 and earlier List of geologic names Bulletin 191 (29MB)
1936 and earlier New and revised names Bulletin 896 — Part 1 (A-L) (68MB), Part 2 (M-Z) (65MB)
1936 – 1955 List of new names Bulletin 1056-A
1959 and earlier List of names Bulletin 1056-B
1936 – 1960 New and revised names Bulletin 1200 — Part 1 (A-F) (85MB),
  Part 2 (G-O) (85MB), Part 3 (P-Z) (86MB)
1961 – 1967 New names Bulletin 1350 (66MB)
1968 – 1975 New names Bulletin 1520 (19MB)
1975 and earlier List of names Bulletin 1535 (25MB)
1976 – 1980 New names Bulletin 1564 (12MB)
1981 – 1985 New names Bulletin 1565 (27MB)
Changes in stratigraphic nomenclature adopted by the USGS
Year addressed by publication USGS Publication
1952 - 1963 U.S. Geologic Names Committee, Changes in geologic nomenclature (unpublished): U.S. Geological Survey. The Committee's copy is available for viewing.
1963 Cohee, G.V., and West, W.S., 1965, U.S. Geological Survey Bulletin 1194-A, 34 p.
1964 Cohee, G.V., and West, W.S., 1965, U.S. Geological Survey Bulletin 1224-A, 77 p.
1965 Cohee, G.V., and West, W.S., 1966, U.S. Geological Survey Bulletin 1244-A, 60 p.
1966 Cohee, G.V., West, W.S., and Wilkie, L.C., 1967, U.S. Geological Survey Bulletin 1254-A, 43 p.
1967 Cohee, G.V., Bates, R.G., and Wright, W.B., 1969, U.S. Geological Survey Bulletin 1274-A, 59 p.
1968 Cohee, G.V., Bates, R.G., and Wright, W.B., 1970, U.S. Geological Survey Bulletin 1294-A, 55 p.
1969 Cohee, G.V., Bates, R.G., and Wright, W.B., 1970, U.S. Geological Survey Bulletin 1324-A, 41 p.
1970 Cohee, G.V., Bates, R.G., and Wright, W.B., 1971, U.S. Geological Survey Bulletin 1354-A, 38 p.
1971 Cohee, G.V., and Wright, W.B., 1972, U.S. Geological Survey Bulletin 1372-A, 28 p.
1972 Cohee, G.V., and Wright, W.B., 1974, U.S. Geological Survey Bulletin 1394-A, 93 p.
1973 Cohee, G.V., and Wright, W.B., 1975, U.S. Geological Survey Bulletin 1395-A, 68 p.
1974 Cohee, G.V., and Wright, W.B., 1975, U.S. Geological Survey Bulletin 1405-A, 36 p.
1975 Cohee, G.V., and Wright, W.B., 1976, U.S. Geological Survey Bulletin 1422-A, 84 p.
1976 Sohl, N.F., and Wright, W.B., 1977, U.S. Geological Survey Bulletin 1435-A, 151 p.
1977 Sohl, N.F., and Wright, W.B., 1978, U.S. Geological Survey Bulletin 1457-A, 136 p.
1978 Sohl, N.F., and Wright, W.B., 1979, U.S. Geological Survey Bulletin 1482-A, 91 p.
1979 Sohl, N.F., and Wright, W.B., 1980, U.S. Geological Survey Bulletin 1502-A, 138 p.
USGS Geologic Names Units (GNU) records