These tiny little plants are Crassula lanceolata subspecies transvaalensis, the smallest of the Crassula species and many people mistake them for moss. I don't have a macro lens that would do justice to these small flowers but if you look closely, you'll just make them out:
People who grow succulents will also recognise the shape as they are one of the columnar types of crassula. You have to look very closely to spot these little plants growing in among the stones on the hill and the spring months are best, before the grass really starts growing and covers them over and protecting them from the sun for a few months.