Limestone is a sedimentary rock, formed approximately 350 million years ago on the bed of a tropical sea.  The horizontal layers of rock are called bedding planes.   Vertical cracks in the rock caused by huge earth movements are called joints.   Limestone is a permeable, pervious rock because it allows water to pass through it by travelling along the joints and bedding planes.

Terracettes are formed by soil movement.  This is called Soil Creep.   When the underlying rock becomes saturated during periods of heavy rainfall then the water can no longer pass through the rock.  The soil then becomes saturated.   The soil particles expand and then contract as they dry out.  This causes them to creep slowly downhill.  This causes ridges to form on the hillside known as Terracettes.