He is always joking around during class.

The geology of this area is mainly composed of serpentinite.

This mountain is made of phonolite.

The bedrock of this area is very hard.

The hyrax lives in the rocky areas of Africa and the Middle East.

This mountain is mainly composed of quartzite.

This area is rich in pitchstone.

This stratum is mainly composed of mudstone.

This area is rich in porphyrite.

The rock-wallaby is a small kangaroo native to Australia.