principle of original horizontality example

The shells were washed up during the Biblical flood.Authors in that day thought that the fossils of marine animals found in tall mountains, miles from any ocean could be explained in one of two ways: Most people at the time did not believe that fossils were once part of living creatures. Steno was struck by the resemblance of the shark’s teeth to fossils found in inland mountains and hills ( Figure below).įossil Shark Tooth (left) and Modern Shark Tooth (right). In 1666, a young doctor named Nicholas Steno dissected the head of an enormous great white shark that had been caught by fisherman near Florence, Italy.

If you find a fossil of a fish in a dry terrestrial environment did the fish flop around on land? Did the rock form in water and then move? Since fish do not flop around on land today, the explanation that adheres to the philosophy that natural laws do not change is that the rock moved.

Geologists always use present-day processes to interpret the past. Knowing that natural laws never change helps scientists understand Earth’s past because it allows them to interpret clues about how things happened long ago. Water freezes at 0° C at 1 atmosphere pressure this is always true. They are the same today as they were billions of years ago. Something that we hope you have learned from these lessons and from your own life experience is that the laws of nature never change.

Know how to use fossils to correlate rock layers.

Explain what an unconformity represents.

Based on a geological cross-section, identify the oldest and youngest formations.

Explain Steno’s laws of superposition and original horizontality.

Principle of original horizontality example