Different Types of Ringforts
A less common variety of ringfort, termed platform ringfort, was characterized by an interior platform raised above the height of the surrounding landscape.  This morphological variation helped to avoid the problem of water logging, but it ultimately left the fort more visible to enemies.  Another type of ringfort, called a cashel, consisted of circular stone ramparts rather than concentric earthen banks and ditches.
[iv]  Cashels were most commonly found in the west of Ireland.