geologic periods

[tonyf@ucmp1.Berkeley.EDU (Tony Fiorillo)]

On Tue, 10 Jan 1995, Tom Holtz wrote:

The Cretaceous is THE longest formal period in Earth's history.  It was 15
million years longer than the whole of the Cenozoic.  Dinosaur species
averaged only some 3-6 million years or so.

***

At the level of geologic period, the Cambrian was longer by several millions
of years (approximately 90 vs approximately 75).  Obviously the Precambrian
is a formal period of time and is the longest formal time increment.

Cheers,
*************************************************************
Tony Fiorillo                                Museum Scientist
Museum of Paleontology                          (510)642-9964 
University of California
Berkeley, CA  94720                  tonyf@ucmp1.berkeley.edu
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