Unit 6 Crossword Puzzle

The scientific study of fossils
A unit of geologic time that includes tow or more periods
A type of fossil that forms when sediments fill the cavity left by decomposed organisms
An arrangement of rock layers in which the oldest rocks are at the bottom
The time needed for half of a sample of a radioactive substance to undergo radioactive decay
A unit of geologic time into which eras are divided
Any method of measuring the age of an event/object
Any method of determining whether an event or object
The death of every member of a species
A principle that states that geologic change occurs suddenly
A fossilized mark that is formed in soft sediment by the movement of an animal
A type of fossil that forms when sediments fill in the cavity left by a decomposed organism
A fossil that is found in the rock layers of only one geologic age and that it used to establish the age of the rock layers
The remains/ physical evidence of a preserved organism