What is geology?
Geology is the study of the Earth’s history, structure and composition over millions of years. To really appreciate the South Downs landscape you need to understand how it was formed.
Geology in the South Downs
Seven Sisters cliffs near Eastbourne
The rocks that form the Downs and the Weald are made from sediment, such as sand or mud, which has gradually hardened into rock. These sediments were laid down in both seas and freshwater lakes many millions of years ago. Most of the rocks that make up the South Downs were formed 120 million years ago. These rocks were then uplifted by earth movements and pushed up into a huge dome about 125 miles long and 50 miles wide. This dome was then worn away mainly by rivers to form the North Downs, South Downs and the plain of the Weald.
The main types of rock that appear at the surface of the ground in the South Downs are shown below.
