Sea stacks - Scotland, Ireland and elsewhere

[Astronuc]

I saw a video of the 'Old Man of Hoy' taken by someone on a ferry passing the coastline.

I had to look up the subject of sea stack or stac.

https://en.wikipedia.org/wiki/Stack_(geology)

A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion.

Stacks typically form in horizontally bedded sedimentary or volcanic rocks, particularly on limestone cliffs. The medium hardness of these rocks means medium resistance to abrasive and attritive erosion. A more resistant layer may form a capstone. (Cliffs with weaker rock, such as claystone or highly jointed rock, tend to slump and erode too quickly to form stacks, while harder rocks such as granite erode in different ways.

https://en.wikipedia.org/wiki/List_of_sea_stacks_in_Scotland#Main_list
https://en.wikipedia.org/wiki/Old_Man_of_Hoy

I'm much more familiar with the The Twelve Apostles off the southern coast of Victoria, Australia.
https://en.wikipedia.org/wiki/The_Twelve_Apostles_(Victoria)
https://en.wikipedia.org/wiki/Twelve_Apostles_Marine_National_Park

https://www.parks.vic.gov.au/places-to-see/parks/twelve-apostles-marine-national-park

Similar features in the Bay of Fundy, Nova Scotia, Canada
https://www.parcsnbparks.info/en/parks/33/hopewell-rocks-provincial-park
https://www.novascotia.com/see-do/attractions/cliffs-of-fundy-unesco-global-geopark/7748

 

[berkeman]

https://en.wikipedia.org/wiki/Stack_(geology)

Looks like they are irresistible to helicopter pilots...