The first lintel of the inner passage
A progression of these edge-set lintels continues back from this stone, roofing most of the length of the inner passage.
The walling above the lintel is the facing of the cairn core, the joints on either side are where the primary casing meets this.
Unlike some tombs of this type, the passage walls do not show a joint at the point where the casing meets the core, the walls
cross the transition line without visible interruption.