Blocked up gates are not uncommon on the dry stone walls of the North York Moors. I always thought they were created when a gate was redundant and so blocked up permanently. But I recently read that in parts of Ireland phantom gates are traditionally used as a normal method closing a gateway. To move cattle or sheep the wall must be taken down and rebuilt. A lot of work. There is a shortage of wood in the windswept Aran Islands, Connemara or County Clare but this method of blocking up gateways has been adopted principally to prevent the winds from blowing across the exposed fields. I am not convinced however that this explanation is applicable to the North York Moors.
Until recently both sides of this wall on Ryston Bank was heavily forested. It has now been clear felled revealing a grand view of Roseberry Topping. The 1839 Tithe Map of Pinchinthorpe names the field the other side of the wall as “Browns Intake”. A field boundary is shown, most likely this wall. The 1893 Ordnance Survey shows the intake field as wooded. My guess is that the wall dates from the 18th century Enclosure Acts with a (wood) gate to allow stock to pass from the intake field onto the moor for summer grazing. Sometime prior to 1893 Brown’s Intake was set to woodland and the gate blocked up to keep the sheep out.