CHAPTER XII.

GEOLOGICAL CHRONOLOGY--PRINCIPLES OF THE SYSTEM EXPLAINED AND DEVELOPED.

Significance of Fossil Remains--Science of Palæontology--Classification of existing Animal Life--Fossil Remains are found to fit in with this Classification--Succession of Organic Life--Time in Geology not measured by Years and Centuries--Successive Periods marked by Successive Forms of Life--The Geologist aims at arranging these Periods in Chronological Order--Position of the various Groups of Strata not sufficient for this purpose--It is accomplished chiefly through the aid of Fossil Remains--Mode of proceeding practically explained--Chronological Table, 198