KNOWN MAXIMUM 
THICKNESS OF 
ERA PERIODS LIFE BEGAN LASTED SEDIMENTARY 
ROCK IN 
N. AMERICA 
Recent AGE OF 1 million still 
Quaternary Pleistocene MAN years ago continues 
CENOZOIC AS ean 
(recent life) Pliocene 61,000 ft. 
Miocene AGE OF 60 million 59 million years 
perSery i Oligocene MAMMALS years ago years 
ROCKY MOUNTAIN CONSTRUCTION EROSION INTERVAL 
einige Comanches AGE 170 milli 110 milli 
amene an million million 
(intermediate life) Jurassic REPTILES year years 86,000 ft. 
Triassic 
APPALACHIAN MT, CONSTRUCTION EROSION INTERVAL 
Permian Ber el a eee =| 
Pennsylvanian AGE 
Mississ AMPHIBIANS 
PALEOZOIC 
(ancient life) Devonian AGE OF 500 million 330 million 
: Silurian FISHES years ago years 110,000 ft. 
Ordovician | AGE OF 
Cambrian INVERTEBRATES 
GRAND CANYON-KILLARNEY REVOLUTION EROSION INTERVAL 
PROTEROZOIC AGE OF 1,000 million 500 million 
(early life) FORMS OF LIFE foes cus 
WORLD WIDE MT. CONSTRUCTION EROSION INTERVAL Total 257, pie ft. (about 
50 he es ce beginnin ng 
ARCHEOZOIC 1,850 + million 850+ million F ea abeice period. 
(beginning life) | years ago years 
Table 1: 
Shows Eras and Periods of Geologic Time and the Appearance of Higher Types of Life with Advancing Time. 
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