3. A much more common form of camp in Devon and Cornwall is one that is circular or oval, and consists of concentric rings of earth, or earth and stone mixed, with ditches between.
There is, however, a variant where a headland is fortified, either one standing above the sea into which it juts, or at the junction of two streams. There it sufficed to run defensive banks and ditches across the neck of the promontory.
This description of camp or castle is usually supposed to be Celtic.
In Ireland such a camp is a rath. The same word is employed for similar camps in a portion of Pembrokeshire.
Every noble had a right to have a rath, and every chief had his lis or dun.
A lis was an enclosed space, with an earth-mound surrounding it, and was the place in which justice was administered. Lis enters into many place-names in Cornwall, as Liskeard, Lesnewth, Listewdrig, the court of that king who killed S. Gwynear and bullied S. Ewny and the other Irish settlers; Lescaddock, Lescawn, Lestormel, now corrupted into Restormel.
In Ireland les had a wider meaning. S. Carthagh was throwing up a mound around a plot of land where he was going to plant a monastery.
"What are you about there?" asked an inquisitive woman.
"Only engaged in the construction of a little lis," was the reply.
"Lis beg!" (small lis), exclaimed the woman. "I call it a lis mor" (a big lis). And Lismore is its name to this day.