History of Geologic ages

	Revision 7 . . August 17, 2001 4:31 am by Don Kenney [*Added reference to GSSPs]
	Revision 6 . . (edit) April 3, 2001 3:20 am by Larry Sanger

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Added: 1a2,3

In 1977 The Global Commission on Stratigraphy started an effort to define global references (GSSPs) for geologic periods and faunal stages.