The rocks are a mélange , often referred to as the Gwna Mélange , which contain an extraordinary mix of clasts of all sizes up to 100m across and of very varied types , including both sedimentary and igneous origin .
The rocks are a mélange , often called Gwna Mélange , which have an unusual mix of clasts of all sizes up to 100m across . These are also very varied types , including both sedimentary and igneous rocks .