__________________________________________________________________________ | | | | YEARS | NUMBER OF | | | ORDER OF NECESSARY FOR | FEET IN | GEOLOGICAL | GEOLOGICAL | APPEARANCE OF FORMATION | THICKNESS | AGE | EPOCH | CHARACTERISTIC | | | | GROUPS ______________|___________|______________|_______________|________________ | | | | | | | | M B R A F I | | | | a i e m i n b | | | | m r p p s v r | | Recent | | m d t h h e a | | or | | a s i i e r t | | Quaternary | | l l b s t e | | | | s e i e s | | | | s a - ______________|___________|______________|_______________|_|_|_|_|_|_|____ | | | | | | | | | | | | | Pleistocene | | | | | | | | | Cenozoic | Pliocene | | | | | | | 5,000,000 | 25,000 | or | Miocene | | | | | | | | | Tertiary | Oligocene | | | | | | | | | | Eocene | | | | | | | ______________|___________|______________|_______________|_|_|_|_|_|_|____ | | | | | | | | | | | | Mesozoic | Cretaceous | | | | | | | 4,000,000 | 23,000 | or | Jurassic | | | | | | | | | Secondary | Triassic | | | | | | ______________|___________|______________|_______________|_____|_|_|_|____ | | | | | | | | | | | Permian | | | | | | | Palaeozoic | Carboniferous | | | | 21,000,000 | 106,000 | or | Devonian | | | | | Primary | Silurian | | | | | | Cambrian | | | ______________|___________|______________|_______________|________________ | | | | 20,000,000 | 30,000 | Azoic | Archaen | ______________|___________|______________|_______________|________________