“…Until recently, these studies and other similar observations in the United Kingdom (Goldie, 1996;Sweeting, 1966;Huddart, 2002) have provided a somewhat confusing range of proposed rates of surface lowering, but more recent studies (focused on Yorkshire but considering the Burren evidence as well) have accounted for the variation through a consideration of a number of potential factors: differing methods for measuring pedestals used by different researchers, differing rates of bedrock dissolution in subaerial environments compared to subsoil environments (and variations in soil chemistry in subsoil environments), variations in local topography and lithology, a preexisting surface of steps and plinths upon which the boulders were deposited, and the possible contribution of mechanical weathering mechanisms such as freeze-thaw cycles at some locales (Goldie, 2005;Parry, 2007). Out of these possibilities, Goldie (2005) dismisses mechanical weathering as probably not being a significant factor on the relatively hard limestone of the Burren, and Parry (2007) argues cogently against mechanical weathering even on other "weak" limestones.…”