He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.
Further, he proposed that wherever un-contorted layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger.
- roberto martinez dating
- amanda bynes dating black man
- speed dating victoria tx
- dating someone who has cancer
- Bull cuckold free chat
- dating love in lv
- elitedatinggroup co uk
Using these key or index fossils as markers, geologists began to identify a particular layer of rock wherever it was exposed.
Because fossils are believed to record the slow but progressive development of life, geologist use them to identify the relative age of rocks throughout the world.
Geologists have divided the Earth's history into Eras -- broad spans based on the general character of life that existed during these times -- and Periods -- shorter spans based partly on evidence of major disturbances of the Earth's crust.
The "relative" positions of layers and fossils to assign estimated dates to strata.
Have you ever wondered how science knows the age of a fossil? If you think of a fossil, surely the first thing that comes to your mind is a dinosaur bone or a petrified shell that you found in the forest, but a fossil is much more.