Further to the north still, sandwiched between these intake fields and the steep slopes of the Pennine escarpment itself lies a complex geological zone known as the Cross Fell Inlier (see Burgess and Wadge). It consists of a lens of older rocks faulted upwards between the much younger layers that bound it. The whole North Pennines AONB, of which the Inlier forms part, is in fact of such interest to geologists that in 2003 it was designated a Geopark under a Unesco programme to promote public interest in geology.