The mushroom rocks grouped on the wave-cut platform are formed with globe-shape rocks on the top while supporting by the thin stone pillars on the bottom. Queen’s Head is the most famous mushroom rock in Yehliu.
The formation process of mushroom rock can be divided into three phases:
Two broken concretions within rock layers are formed vertical to the sea level; as a result, the erosion caused by seawater may progress along the concretions, leading to the formation of stone pillar lining up in row.
The formation of mushroom rock is caused by differential erosion as the top rock layer containing calcium and being more durable for erosion than the lower rock layer.
The mushroom rock as formed is under continuous plate extrusion and thus is raised above sea level. Once it’s exposed to the planet’s atmosphere, it will suffer from weathering as well as rain erosion and turn into the shape as we see it now.
The mushroom rocks can be divided into three types according to the difference appearances as manifested on the head and neck of the rock: “Thin-neck rock”,” thick-neck rock” and “neckless rock”. As many of the thin-neck mushroom rocks undertake heavier load on the top and they may be toppled down easily if striking by earthquake or violent winds and waves.
The mushroom rocks may turn into various kinds of shapes in a progressive manner as they are chronically eroded by wind, sun and rain. They may involve into neckless rock, thick rock, thin rock and even the broken-end rock eventually. The top of the thin rock may fall apart if the neck of the rock contains incomplete sands and thud accelerating the formation of broken-end rock.