... varied from the most recent period in the area, the Carboniferous to the most ancient in the area, the Precambrian. No close up examination of Cambrian or pre-Cambrian rock landscapes or beds took place. However at Settling Nose, just north of Broadhaven Cambrian and pre-Cambrian rock could be observed to the north, stretching west (Cambrian) to east (pre-Cambrian). These are volcanic rocks which form the majority of the headland to the north, St. David's Head. However several boulder sized Pre-Cambrian rock pieces were found at Settling Noses. These rocks were green and had rhombic crystals under examination. The rock is therefore classified as rhom porphyry. This rock is described as an erratic as it is so dissimilar to the rock type of the landscape it is found in. A glacier has most likely moved it, as the only other possible mechanism for movement is a river, which is unlikely, ...

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