Granite forms the highlands of Land's End, Bodmin Moor and Dartmoor. It was formed from layers of sediment which were washed into the sea by rivers many millions of years ago. The upper layers of sediment pressed down on the lower layers and this pressure cemented the separate grains of material into rock. Limestone was formed in a similar way from the remains of dead sea creatures. Sedimentary rocks often contain the fossils of larger sea creatures which died and were buried.
Sedimentary rocks are softer than igneous rocks and erode more easily.