Geological Time Scale Crossword

What is the geologic age of a fossil organism, rock, or geologic feature or event defined relative to other organisms, rocks, or features or events rather than in terms of years.
Preserved remains or traces of animals, plants, and other organisms from the past
The amount of time it takes for half of a remaining isotope to decay to a daughter product
A fossil that is useful for dating and correlating the strata in which it is found.
A layer or a series of layers of rock in the ground.
A basic law of gerontology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom
The geologic age of a fossil, or a geologic event or structure expressed in units of time, usually years. Also known as actual age.
An igneous intrusion is always younger than the rock it cuts across
Inclusions found in other rocks or (formations) must be older than the rock that contain them.
Any division of geological time into chronological units, whether relative or absolute.