Original: The Malvern Hills, which run from the south of the county into Herefordshire, are made up mainly of volcanic igneous rock and metamorphic rock, some of which date from before 1200 million years ago.
Simplified: The Malvern Hills, which run from the south of the county into Herefordshire, are made up mainly of volcanic rock, some of which date from before 1200 million years ago.