Ruskin, it is definitely a natural hill! No doubts exist on that point. The "usual" reason for a hill in this sort of location is that it is one or more of the following: 1 consists of more resistant rock than its surroundings, so erodes more slowly = higher 2 if its no more resistant than its surroundings, then it may have been protected by a cap of more resistant materials in the past, slowing down its erosion 3 rivers may have followed easier routes which took them around the hill, leaving it relatively higher as they eroded the lower land surrounding the hill 4 it may be a geological formation whose structure makes it less easy to erode I am not sure which particular explanation is the one in this case.