Federal Geographic Data Committee, Geologic Data Subcommittee, 2006, FGDC digital cartographic standard for geologic map symbolization: Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 pls., available online at
Orndorff (chair), Nancy Stamm (recording secretary), Steven Craigg, Lucy Edwards, David Fullerton, Bonnie Murchey, Leslie Ruppert, David Soller (all USGS), and Berry (Nick) Tew, Jr.
In the ICS time scale, the uppermost part of the Cambrian has been named "Furongian" and the lowermost part the "Terreneuvian." The GNC, however, will not include these names in the Divisions of Geologic Time until all series/epochs of the Cambrian are named.
A controversial issue during the first decade of the 21st century was the position of the base of the Quaternary System/Period and its status as a formal division of time.
Also of note, the Ediacaran is the only formal system in the Proterozoic. B., van, eds., 1998, Geological time table (5th ed.): Amsterdam, Elsevier, 1 sheet.