The cone-bearing plants prominent during the entire Mesozoic occu-
pied only a secondary r ole during the Cenozoic.Tropical vegetation that was
widespread during the Mesozoic withdrew to narrow regions around the
equator in response to a colder, drier climate, resulting from a general uplift of
the continents and the draining of the interior seas. Forests of giant hardwood
trees that grew as far north as Montana are now occupied by scraggly conifers,
a further indication of a cooler climate.
The rise of the angiosperms might have even contributed to the death of
the dinosaurs and certain marine species at the end of the Cretaceous.By absorb-Figure 164A fossil leaf
from the Raton
Formation near Trinidad,
Colorado.
(Photo by W.T. Lee,
courtesy USGS)
Historical Geology