Prior to the late 17th century, geologic time was thought to be the same as historical time.
Archbishop James Ussher of Armagh, Ireland, 1654, added up generations from the Old Testament and determined that Earth formed on October 23, 4004 BCE.
From the beginning of this course, we have stated that the Earth is about 4.6 billion years old.
Principle of Superposition Because of Earth's gravity, deposition of sediment will occur depositing older layers first followed by successively younger layers.
In fact, sedimentary rocks are, in a sense, trash from the Earth's surface deposited in basins.