| ERA
|
mya |
PERIOD |
|
| Cenozoic Era
(Age of recent life)
|
2
65 |
Quaternary Period
|
The several geologic
eras were
originally named Primary, Secondary, Tertiary and Quaternary. The
first two names are no longer used. |
|
Tertiary Period |
| Mesozoic Era
|
145
213
248 |
Cretaceous Period
(Coon Creek
time) |
Derived from Latin word for chalk and
first applied to extensive deposits that form white cliffs along the
English Channel. |
|
Jurassic Period |
Named for the Jura
Mountains, located between France and Switzerland, where
fossils of this age were first
identified. |
|
Triassic Period |
Taken from the word "trias" in
recognition of the threefold characters of these fossils in Europe. |
| Paleozoic Era |
286
320
360
400
440
500
544 |
Permian Period |
Named
after the province of Perm, in Russia, where these fossils
were first studied. |
|
Pennsylvanian Period |
Named
for the state of Pennsylvania where there is a lot of coal. |
|
Mississippian Period |
Named
for the Mississippi River Valley where fossils of this
Period are exposed. |
|
Devonian Period |
Named
after Devonshire, England, where these fossils were first
studied. |
|
Silurian Period |
Named
after a Celtic tribe, the Silures, that lived in Wales after
the Roman Conquest. |
|
Ordovician Period |
Named
after a Celtic tribe, the Ordovices, that lived in Wales
after the Roman Conquest. |
|
Cambrian Period |
Take
from the Roman Name of Wales (Cambria) where fossils
containing the earliest forms of life were studied. |
| Precambrian Time |
2500
3800
4500 |
Proterozoic Era |
The
Time between the birth of the planet and the appearance of
complex life forms. More than 80% of the earth's
estimated 4-1/2 billion years falls within this era. |
| Archaean Era |
| Hadean Time |
