Precambrian

first era of geologic time; origin of the earth

paleozoic

second era of geologic time known for age of fishes and rise of reptiles

mesozoic

third era of geologic time known as the age of dinosaurs

cenozoic

current era of geologic time see the rise of mammals and modern man

triassic

first period of the mesozoic era dinosaurs first appear

jurassic

second period of the mesozoic era

cretaceous

last period of the mesozoic era dinosaurs and many other life forms become extinct at the end of this period

replacement

process of fossil formation when the original material is replaced by mineral deposits

carbon imprint

process of fossil formation that occurs as the original object is compressed to mleave an imprint made of carbon

trace fossils

these are not the remains of animals but burrows footprints and evidence of feeding

coprolite

fossilized dinosaur dung

ornithischians

bird-hipped dinosaurs

saurischians

lizard hipped dinosaurs