Igneous rocks similar to the Jake rock are well known but occur rarely on Earth.

Igneous rock occurs in two ways.

The name is derived from Ravenscar on the North Yorkshire coast where rocks of this age occur.

The glassy, hard, often translucent rocks occur at only a few known sites around the world.

Conditions producing widespread regionally metamorphosed rocks occur during an orogenic event.

No rocks earlier than the Proterozoic occur at surface within England.

A rock is a naturally occurring solid, made of minerals.

There is no indication that igneous rock occurs where the thermal springs discharge.

Jurassic rocks occur over a wider area to the west and south but are also absent under London itself.

Porphyritic rocks occur between the schists and the quartzites.