Prehistoric Puzzle Crossword

Study of fossils of animal and plant life that existed in remote geological times
Fossils used for age dating and correlating Cenozoic era
The bryozoans and foraminifers appeared during this period
The first vertebrates and earliest corals appeared during this period
First air breathing animal fossils were found in Scandinavia and Great Britain during this period
The seas contained echinoderms and foraminifers during this period
The disappearance of many forms of marine animals and the rapid spread of reptiles appeared during this period
This era is often called the Age of Reptiles
The dinosaur first appeared during this era about 255 million years ago
A four-footed armored dinosaur during the Jurassic Period
The triceratops was added to the tribe of dinosaurs during this period
The titanotheres and the oreodonts existed during this period
This period is regarded by zoologists as the Age of Mammals
The process of comparing the ages of rock layers
Uses special scientific instruments to determine the actual age of the rock
An undisturbed layer closest to the surface is youngest and each layer below it is older
Used to determine the age of igneous rocks
Rocks breaking down by wind, water, rain and ice
The removal of weathered rock from it's original place
Used to determine what the environment of an era was like long ago