From Stories of the Border Marches by John Lang and Jean Lang, 1916.
"Local tradition tells also how once on a time there came to Sewingshields, to visit Arthur, a great chieftain from the wild north, one named Cumin. And when Cumin departed from the castle to go back to his own land, he bore with him a certain gold cup that Arthur, in token of friendship, had given to him. But sundry of the King's retainers, having learned that the Scot was bearing away with him this cup, greatly desired that they might themselves possess it, and they pursued Cumin, and slew him ere he had gone many miles. Wherefore Arthur caused a cross to be erected there on the spot where the slain man fell; and the place is called Cumming's Cross to this day."
The Archaeology (From 'Keys to the Past')
Comyn's Cross (Wark)
"These are the remains of a stone cross standing on the line dividing open moorland from farmland. It stands about one metre high. On the south face is a cross, formed by small carved rosettes. The cross was more likely to have been placed here to mark a land boundary in the 12th-15th centuries."