For the main description, and for a view from another angle, see
NS4673 : An old ford.
As noted there, the foreground feature in the burn is on the line of an old track. The course of that track, which is still discernible in satellite imagery, was marked on OS maps from 1860 to just before the Second World War. The track clearly fell into disuse, though, several decades ago. The feature here in the burn is not marked on any maps, but appears to have been a ford.
In the present photograph, the line of the old track continues directly ahead, passing just to the left of
NS4673 : A small fenced enclosure, which can be seen not far ahead on the right (it merely contains some metal covers, and it is almost certainly unconnected with the old track).
For a view across the old ford from the other side, see
NS4673 : An old ford. Relative to that view, the old track ended about 20 metres beyond the ford, where it met the present-day track that is shown in that picture (that track already existed when the first OS maps of this area were surveyed in 1860).