age position of the genus Apatosaurus

[John Schneiderman <dino@revelation.unomaha.edu>]

I heard some years ago that Robert Bakker was working on a correlation of 
Apatosaurus species against the stratigraphic levels of the Morrison 
Formation (probably using the Como Bluff region as the model).  Has anyone 
seen this work...Bakker had a graphic representation of his work but I only
saw a 1.5 second glance of it.

I have generally placed all the Apatosaurus species at about 140 million 
years ago.

Apatosaurus ajax
Apatosaurus excelsus (=Brontosaurus excelsus)
Apatosaurus louisae
Apatosaurus yahnanhensis

---John Schneiderman (dino@revelation.unomaha.edu)