(1). For argument's sake, first there was a simple coastline.

(2). During a warm interglacial when the sea level was about 15 feet higher than present sea level, over thousands of years the sea eroded a wave cut platform slightly below sea level and created a high cliffline.

(3). During an ice age the sea level dropped due to water being locked up in huge ice sheets, and a seesaw effect as scotland was pushed down under the weight of ice.

This formed a cliffline about 150m below present sea level.

(4). The local environment was tundra, freezing during the winter and thawing in the summer. This through freeze thaw action produced a huge amount of erosion, the eroded material slowly pored over the edge of the old cliff by the process of solifluction and slumped down creating the concave sloping head.

(5). The sea level then rose again to the present level, which is below the original level.

(6). The head being unconsolidated eroded much more rapidly than the old wave cut platform below it. Thus leaving a raised beach, and a head cliff in front of the fossilised cliffline of the past. It is possible to see raised beaches at more than one height which is due to the process having repeated at slightly different sea levels.