Table 7.1 Geologic Time Chart 



[Quaternary] 



[Tertiary 

 CENOZOIC 



MESOZOIC 



Pleistocene 



Pliocene 



Miocene 



Oligocene 



Eocene 



Paleocene 



Modern gen(!ia and s|)e(ies ol" animals. Domi- 

 nance of man. 



Many larj^e nianii 

 Prehistoric men. 



)!' types now extinct. 



During: these periods mammals increased in 

 specialization, many j^roups attaining their 

 maxima. 



In these periods ancestral representatives of 

 most modern orders of manunals appeared. 

 Archaic manunals attained their maximum 

 in Eocene; most became extinct at its close. 



Cretaceous P'irst flowering plants (angiosperms) ; de- 



ciduous trees first abimdant. Dominance of 

 dinosaurs. Marsupial and placental mam- 

 mals. 



Jurassic Maximum of ammonites. Belemnites. Insects 



al)undant, including social insects. Domi- 

 nance of dinosaurs. First birds: Archae- 

 opteryx. Early mammals; Pantotheria. 



Triassic Maximum of labyrinthodont amphil)ians. 



First dinosaurs. Manmial-iike reptiles: 

 Therapsida. 



PALEOZOIC 



Permian 



Pennsylvanian 



Mississippi AN 



Devonian 



Silurian 



Ordovician 



Cambrian 



Expansion of ammonites. Last of trilobites. 

 Expansion of reptiles: Cotylosauria, Therap- 

 sida. 



Luxurious vegetation, forming coal. First 

 insect fossils. Many lal)yrinthodont am- 

 phibians. First reptiles. 



Foraminiferans. spiny brachiopods, and 

 crinoids abimdant. Few corals and trilobites. 

 Many shell-crushing sharks. Amphibians. 



Bracliiopods. corals, and crinoids aljundant. 

 Trilobites declining. First ammonites. Ter- 

 restrial plants and animals, spiders. Domi- 

 nance of fishes. First amphibians. 



Corals, brachiopods, and crinoids abundant. 

 Triloliites beginning to decline. h]urypterids 

 prominent. Scorpions and millipedes. Os- 

 tracoderms and placoderms. 



First corals, crinoids, nautiloid cephalopods, 

 ostracods. Graptolites, brachiopods. snails, 

 and triloiiites alnmdant. First vertebrates. 



Dominance of trilobites. Brachiopods. Cal- 

 careous sponges. Many other invertebrates; 

 no vertebrates. Ceplialo[)o(ls appeared near 

 its close. 



PROTEROZOIC 



Few fossils: annelid worm burrows, cal- 

 careous deposits by algae. Graphite. 



ARCHEOZOIC 



Calcareous deposits by algae 2,600,000,000 

 years old; graphite. 



