This is from the Manx notebook just in case your info is from a different source

In this parish is Cronk-na-Marroo, ye., the Hill of the Dead, one of the largest mounds in the island. It is upwards of twelve feet high, forty feet in length, and twenty in breadth. It is situated on the sea cliff, across the isthmus of a small insulated crag overhanging the beach. The neighbouring lands, in some old records of the Duchy of Lancaster, are called Torkilstadt, from which it is supposed the celebrated Danish Viking. Thorkell the Tall, once settled here. If this be correct, perhaps Cronk na Marroo may have something to do with his excursions. Near Cronk na Harrow is the small Bay of Greenick from the Norsk, Greenvig, or Green Bay, and a little south of Greenick, the Creek Saltrrik. The rocks in this vicinity are very grand. There are several caverns on the beach. A very remarkable one galled Wallberry, which, from its stygian character, is sometimes alluded to in maledictory expletives by the neighbouring peasantry, On the headland, above Greenick, are two small ancient fortifications; probably used in former times as posts of observation.

On your research on Corkills have you anything on this family from Santan?

James Corkill born around 1720
Married 30 September 1746 Braddan / Santan?
Alice Cowle born 3 May 1719 Santan
Children All born Braddan
*Isabel Born 19 July 1747 (married Thomas Quine)
William Born 19 Feb 1748
James Born 13 Oct 1751
Margaret Born 29 April 1754 (possibly married Andrew Croghan?)
Robert Born 23 July 1757
Mary Born 23 July 1757