The "age of bacteria" would cover more than 3 1/2 billion years, so the term may of limited bio-stratigraphic value. Glen Ledingham --- Lynn Deuschle <lpd4@cornell.edu> wrote: > I once heard S.J. Gould say during a talk that > it is and always has been > the age of bacteria rather than the "age of > dinosaurs" or the "age of > Mammals." >