| A | B |
|---|
| Era | Divisions of Earth's geologic time scale that is futher divided into periods. |
| Cenozoic, mesozoic, Paleozoic | Divisions of time called periods. |
| Fossils | The evidence that allows scientist to piece together the Earth's history. |
| principle of super position | When older layers of rock are found on the bottom and younger layers of rock are found at the top, if the layers are not disturbed. |
| unconformity | When layers of rock are missing from area's geologic history this is called? |
| radiometric dating | A tool that geologist use to determine the relative age of rocks and fossils. |
| Precambrian | An Era when the Earth was formed and bacteria like life forms were prevalant. |
| Paleozoic | A time period when the Appalacian mountains were formed. |
| mesozoic | Era of the dinosaurs. |
| Cenozoic | Era when mammals were abundant. |
| Quaternary period | homo sapiens evolved, Most recent ice ages, and the formation of the Grand Canyon |
| Jurassic period | First birds appeared. |
| epochs | divisions of the cenozoic period. |
| Triassic period | First mammals, Atlantic Ocean begins forming, Pangaea breaks up. |
| mold and cast fossilization | When a shell of an animal becomes encased in sediment that is undergoing compaction and cementation to form rock. |
| Mosasaur | A type of reptile that lived during the Mesozoic Era. |
| Stegosaurus | A plant-eater that lived in the late Jurassic period. |
| Parasaurolophus | A plant-eating, duck-billed dinosaur that lived in the late Cretaceous period. |
| Pterosaurs | Flying dinosaur of the Triassic period. |
| Ichthyosaurs | Swimming dinosaur of the Triassic period. |
