Fossils

Original Paragraph:

Half a billion years ago there was no life on land and only worms, snails, sponges, and primitive crabs in the seas. When these creatures died, their bodies sank into silt and mud and were slowly covered. Over millions of years, the sea bottom hardened into rock and the minerals of the bones were replaced, molecule by molecule, with rock-forming minerals such as iron and silica.
Eventually, this process turns the bones into rock--and they become known as fossils, a slowly created cast of an animal that died hundreds of millions of years ago. Other fossils are formed when dying animals fall into peat bogs or are covered in sand. As each new sedimentary layer takes millions of years to form, we can judge the age of the fossils from their depth. You can travel in time, in fact, if you have a spade.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fossils are very amazing things. It is unreal to know that you can see a person in real life that lived hundreds of years before you, or an animal or plant. People have learned over the years that you can determine the age of trees and rocks and animals that lived a very long time ago just by looking at their fossil. There are many different methods used to decide how old a fossil is and it is a very controversial subject. The fact is that there are fossils and there is proof that things lived a very long time ago, such as dinosaurs, etc. My family and I are going to visit the Grand Canyon over spring break and I know it will be fascinating. The many layers of dirt, rocks, sediment, etc. are full of fossils, I'm sure. I'm looking forward to checking it all out.