Era

Period

Events (Dates given are millions of years ago)

C
E
N
O
Z
O
I
C

Quaternary

Holocene Epoch, date: .01 years ago until present. Rise of man. Humans learn to grow plants, raise animals, use metals. Modern times begin.

Tertiary

Consists of 5 epochs.

Pleistocene. Date: .02 years. Large animals (like wooly mammoth) appear and then die out. Glaciers covered much of the earth.

Pliocene. Date: .53 Ocean and land life resembled that of modern times. Primitive humans appeared.

Miocene. Date: 23.7 Apes develop in Africa and Asia. The Alps and Mimalayas had formed by the end of the period, and the continents are in the form they are today. Earth in "ice age".

Oligocene. Date: 36.6 Primitive apes first appeared. Climates were mild.

Eocene. Date: 57.8 Primitive horses, camels, and monkeys as well as other mammals appeared. Grains and grasses developed.

M
E
S
O
Z
O
I
C

Age of
Dinosaurs

Cretaceous

Consists of 3 epochs.

Paleocene. Date 66.4 More small mammals developed. Climates were varied. This was end of dinosaurs.

Late and Early. Date 144 to 66.4. First seals appear. Dinosaurs reached their peak and then died out. Fruit trees and flowering plants developed. North America's inland sea drained and the Rocky Mountains were formed.

Jurassic

Consists of 3 epochs. Early, Middle, and Late. Date 208 to 144.

An inland sea formed in North America. More dinosaurs appeared and the first birds appeared.

Triassic

Also consists of 3 epochs. Early, Middle and Late. Date 254 to 208.

First redwood trees appeared. The first dinosaurs and small mammals appeared.

P
A
L
E
O
Z
O
I
C

Date:
4,550 to 254

Permian

Cone bearing trees apeared. Climates changed, and glaciers covered many areas. The Appalacian Mountains formed.

Mississippian

Carboniferous. The coal ages. Plant growth in swamy lowlands laid the foundations of later coal deposits. The first reptiles appeared and giant insects developed.

Devonian

The age of Fishes. On land, large fern trees and other plants developed. The first amphibians appeared.

Silvrian

First reefs appeared: stromatoparas, tabulates, rugose, corals and algae.

Ordovician

Seas spread much across North America. Shellfish were plentiful.

Cambrian

Life was restricted to the seas. The first vertebrate, a small fish, appeared.

P
R
E
C
A
M
B
R
A
N

Date:
4,550 and earlier

(No
Period
Names)

Archaeozic Era. Earth's atmosphere gained oxygen. Single celled organisms developed. Complex chemical processes formed large molecules. Earth's surface formed and oceans appeared.