Geologic Principles and Geologic Time

Question 1

Law of Superposition

Answer 1

A rock layer that exists beneath another layer must be older than any rock layer above it.

Question 2

Law of Original Horizontality

Answer 2

A sedimentary rock layer must have been deposited in a horizontal manner and any deformation in the shape of those layers occurred after the rock was initially deposited.

Question 3

Law of Lateral Continuity

Answer 3

Rock layers extend in all directions until they pinch out.

Question 4

Law of Cross-cutting Relationships

Answer 4

Any rock material that cuts through, across, or intrudes another rock layer must be younger than the original rock material it crossed over.

Question 5

Law of Inclusions

Answer 5

Any rock inclusions found in another rock must have come from a pre-existing rock.

Question 6

Law of Faunal Succession

Answer 6

Fossils contained in sedimentary rock layers existed during the same geologic time frame with each fossil succeeding each other in vertical rock layers in a specific, reliable order that can be identified over wide horizontal distances.

Question 7

Law of Uniformitarianism

Answer 7

Natural laws and processes that operate in the universe today have always operated in a similar way throughout the universe in the past.