Devastator Peak was the source for a thick sequence of andesite lava flows that occurred 0.5-1.0 million years ago.
This is one of the thickest sequences in Britain and may be used as the basis for defining these new subzones.
The structure contains a thick sedimentary sequence of sandstone, shale and siltstone.
The western part of the canyon has a much thicker sequence of Muav than the eastern part.
It is a about 557 m thick sequence of poorly consolidated sandstones and siltstones.
This ridge traps sediments, thus allowing for thick sequences to accumulate.
Fore-arc basins are filled with deep marine deposits and thick sequences of turbidites.
Southeast again is the thick sequence of the Raglan Mudstone Formation.
In the northern parts of Flanders it forms an up to 50 meters thick sequence in the subsurface.
It has a diameter of 15-30 kilometers and is made of thick massive mafic sequences.