Page 241 - Laboratory Manual in Physical Geology

Absolute Era (time)
Ages (in and Period (time) and
millions Erathem System (rock) Ranges (black vertical lines) of Index Fossils Pictured Below
of years) (rock) name
name
0.2 Quaternary
2.6 Homo sapiens
CENOZOIC Neogene

23 Tertiary
34 Paleogene Baculites
Fagopsis
trees
66
76
Exogyra
82
Cretaceous
145
MESOZOIC Jurassic

201 Dinosaurs Mammals
210 Inoceramus
225 Triassic

252
255
Neuropteris
ferns
Permian
Sharks
280
299
Reptiles
300 Pennsylvanian
310
323

Mississippian
Chonetes
PALEOZOIC Devonian
359
365 Mucrospirifer Amphibians
397
419
425
Phacops
Silurian
Strophomena
443

450 Ordovician
470 Flexicalymene
485 Platystrophia
500
515 Cambrian
520 Elrathia
Olenellus
541

Precambrian

4550

FIGURE 8.10 Range zones. Range zones (vertical bold black lines) of some well-known index fossils relative to named divisions of the

geologic time scale.
Dating of Rocks, Fossils, and Geologic Events ■ 213