PALEONTOLOGY 



Epochs and Formations 



Faunal Characters 



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PLEISTOCENE. 

 PLIOCENE, 3,000 ft. 



MIOCENE, 4,000 ft. 



OLIGOCENE, 8,000 ft. 

 EOCENE, 10,000 ft. 



Man. Mammalia principally of living species. 

 Mollusca exclusively recent. 



Mammalia principally of recent genera liv- 

 ing species rare. Mollusca very modern. 



Mammalia principally of living families; ex- 

 tinct genera numerous; species all extinct. 

 Mollusca often of recent species. 



Mammalia with numerous extinct families and 

 orders; all the species and most of the gen- 

 era extinct. Modern type shellfish. 



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CRETACEOUS, 12,000 ft. 

 Chalk. 



JURASSIC, 6,000 ft. 

 Oolite. 

 Lias. 



TRIAS, 5,000 ft. 



New Red Sandstone. 



Dinosaurian reptiles; pterodactyls (flying rep- 

 tiles); toothed birds; earliest snake; bony 

 fishes; crocodiles; turtles; ammonites. 



Earliest birds; giant reptiles (ichthyosaurs, 

 dinosaurs, pterodactyls); ammonites; clam 

 and snail shells very abundant; decline of 

 brachiopods; butterfly. 



First mammalian (marsupial) ; 2-gilled cephal- 

 opods (cuttle-fishes, belemnites) ; reptilian 

 footprints. 



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PERMIAN, 5,000 ft. 



CARBONIFEROUS, 26,000 ft. 

 Coal. 



DEVONIAN, 18,000 ft. 

 Old Red Sandstone. 



SILURIAN, 33,000 ft. 



Earliest true reptiles. 



CAMBRIAN, 24,000 ft. 



Earliest amphibian (labyrinthodont) ; extinc- 

 tion of trilobites; first crayfish; beetles; 

 cockroaches; centipedes; spiders. 



Cartilaginous and ganoid fishes; earliest land 

 (snail) and freshwater shells; shellfish 

 abundant; decline of trilobites; May-flies; 

 crab. 



Earliest fish; the first air-breathers (insect, 

 scorpion) ; brachiopods and 4-gilled cephal- 

 opods very abundant; trilobites; corals; 

 graptolites. 



Sponges, jellyfish, annulated worms, Mollusca, 

 brachiopods, Polyzoa, echinoderms no ver- 

 tebrates. 



From Romanes' Darwin and after Darwin, slightly modified. 



