| Era | Time Millions of Yrs Ago Began — Ended | Major Geological Events | Major Biological Events | Canadian Landforms Created |
| Precambrian (earliest life) | 4600 570 | – volcanoes erupted, many cycles of mountain building and erosion | – 1st single-celled organisms – 1st multi-celled organisms | – Canadian Shield formed |
| Paleozoic (ancient life) | 570 245 | – periods when large parts of North America were covered by shallow seas | – 1st insects – Age of Amphibians and Fish – large swamps – 1st plants & animals appear on land | – Appalachian Mountains formed |
| Mesozoic (middle life) | 245 66 | – shallow seas in interior of North America at times | – Age of Reptiles (dinosaurs) – 1st flowering plants – 1st birds and mammals | – Formation of Rocky Mountains begins – Innuitian Mountains formed |
| Cenozoic (recent life) | 66 present | – ice sheets covered much of North America – continents take on present shape | – human beings develop – Age of Mammals – modern forms of life evolved | – Formation of Rocky Mountains completed |
