The fossil record consists of approximately 3 to 3.5 Ga of fossils.  Terrestrial organisms, such as ourselves, are present in only one seventh of that record.  The period of particular interest for terrestrialization is the Devonian.

A Brief History of Time

QuarternaryFrom present to 1.6 Ma.  Continents are configured in thier       present day positions and climates are comparable to today.

TertiaryFrom 1.6 Ma to 65 Ma.  Large radiation of mammals after the extinction of the dinosaurs.

CretaceousFrom 65 Ma to 144 Ma.  Appearance of the first marsupials.

JurassicFrom 144 Ma to 208 Ma.  Appearance of the first birds.

TriassicFrom 208 Ma to 245 Ma.  First appearance of dinosaurs.

PermianFrom 245 Ma to 286 Ma.  Continents in Pangea configuration.

PennsylvanianFrom 286 Ma to 330 Ma.  Appearance of first reptiles.

MississippianFrom 330 Ma to 360 Ma.  Radiation of tetrapods.

DevonianFrom 360 Ma to 408 Ma.  Appearance of first amphibians, (first terrestrial vertebrates).

Silurian408 Ma to 438 Ma.  First vascular plants.

OrdovicianFrom 438 Ma to 505 Ma.  First jawless fish,  (Agnatha).

CambrianFrom 505 Ma to 570 Ma.  Cambrain "explosion " of life.  All phylas established.

ProterozoicFrom 2.5 Ga to 544 Ma. (*There is some debateover the actual placement of the boundry between the Proterozoic and the Cambrian, having to do with the ediacaran fauna of the time.)  No fossil evidence.

ArcheanFrom 2.5 Ga to 4.6 Ga.  No fossil evidence.