At the base there is frequently a conglomerate or tuff of porphyritic rocks.
The metal in its usual slowly cooled state is a conglomerate like the granitic rocks.
The houses being mostly built of a white conglomerate stone of shells and coral which forms the peninsula, gives the city when viewed from a distance a clean and handsome appearance, but on closer inspection the streets are found to be very narrow, irregular, ill-paved and filthy.
It is situated on a platform of conglomerate rock forming a promontory at the south-west of the entrance to Loch Etive and is surrounded on three sides by the sea.
The conglomerate bands and quartzites contain large quantities of iron pyrites deposited subsequent to their formation, that in the conglomerates containing the gold.