Figures 6a and 6b: Iron Age data entries: concentrations of land enclosure along the Magnesian Limestone west of the Vale of York are recorded in the SMR for the north of the region as being definitely of Iron Age date (6a). To the south, they are classified only as broadly late-prehistoric, hence appearing only in the possibly Iron Age distribution (6b) (data used under licence from the British Geological Survey).
| Yorkshire Location Map | a. Iron Age Only Enclosure | b. Iron Age All Enclosure |
| with Magnesian Limest. | with Magnesian Limest. | |
| with elevation | with elevation |