Finnish Turning Stitch, plaited edge, Parikkala style
2+2+tr, plaited edge
tr = 1 loop is 'turned', needle tip to right
UUO Down U/O Up UOOU, connection "under X"
Finnish Turning Stitch, plaited edge, 2+2+tr, Parikkala style
There's a diagram in Kaukonen's article (1960), and the connection stitch is based on the sample in the NBA ethnology collection, label 9616:8(b).
You can read more about the Finnish Turning Stitches on page Stitch Grouping by Toini-Inkeri Kaukonen (link).
Photo on the top - Edge loops
Photo below - Needle points where to make the connection