A VIEW OF THE GRAND CANYON OF THE COLORADO RIVER,
ARIZONA.
ZOROASTER IN BACKGROUND.
Photograph by O. C. Farrington.
Field Museum of Natural History
DEPARTMENT OF GEOLOGY
Chicago, 1927
Leaflet Number 9
How old are Fossils?
“How old is that fossil and how do you know it?” is a question frequently asked by visitors going through the hall of fossils in the Museum. A precise answer to such a question is impossible and an adequate one demands a longer time than can usually be afforded. The consequences of inadequate explanation have often proved to be unsatisfactory. The visitor becomes skeptical and instead of taking interest in the subject, he seems to be confirmed in his doubts.
In this leaflet is given a condensed, general statement of methods of determining the age of ancient life. The information is drawn from the works of various authors, especially Barrell’s “Rhythms and Measurements of Geologic Time.” It is intended for those who are interested in the age of past life and yet do not intend an exhaustive study of the subject, nor have free and easy access to its literature.
The birth of life was the most momentous occasion in the history of the earth. When one considers the myriads of evidences unearthed by paleontologists and paleobotanists, they seem to leave no room to doubt the great conception that the life of the land has emerged from the sea. It is, therefore, only a natural impulse to look for the remains of this life in the rocks laid down by the ancient seas and to wonder at the vastness of time behind them.