The remains of an ancient atoll as a hill in a limestone area is called a reef knoll.
It commands wide views of the dale and sits astride the feet of Cawden hill, a reef knoll.
It was one proposed that in Lancashire, reef knolls could be seen between the villages of Worston and Downham near Clitheroe.
Further double sunsets were discovered by the writer Jeff Kent in 1997 from three places in west Derbyshire, observed against the limestone reef knolls, Chrome Hill, Parkhouse Hill and Thorpe Cloud.
The name of the village can be seen as famous . in geological circles-for the nearby Cracoe Reef Knolls a series of limestone hills which are geological remnants of an ancient coral reef.
"' Thorpe Cloud "'is an isolated limestone hill ( a reef knoll ) lying between the villages of Ilam on the Derbyshire / Staffordshire border at the southern end of Dovedale.
Geologically, the hill is the remains of an atoll ( a'reef knoll') which is believed to have existed during the Carboniferous period when what is now the Peak District was covered by a SSSI, cited for their geology and limestone flora.