Geology Reference
In-Depth Information
◗
Figure 23.17
Cenozoic Diatoms and Foraminifera
b
Cibicides americanus
is a
benthonic foraminifera from
the Early Miocene.
c
Globigerinoides fi stulosus
is a
planktonic foraminifera of Pleistocene
age.
a
Diatoms from the Miocene-age Monterey Formation of California.
◗
Figure 23.18
Vegetation and
Climate
a
Plants adapted to cool
climates typically have small leaves
with incised margins (top), whereas
in humid, warm habitats, they have
larger, smooth-margined leaves, and
many have drip-tips.
b
Climatic
trends for four areas in North
America based on the percentages
of plant species with smooth-
margined leaves.
100
90
Mississippi embayment
30
80
Northern California
25
70
Pacific Northwest
60
20
Southern Alaska
50
15
40
30
10
20
5
10
0
0
60
50
40
30
20
10
0
Millions of years
a
b
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