of what ever is happening in the basement rock. At the western edge of the Blue Mountains the Wallula Fault zone intersects the northeast-striking Hite Fault System (HFS). This system is complex and has been variously interpreted. Although seismically active it appears to be offset by, and thus should be older than, the Wallula fault. On the other hand, a later study found "no obvious displacement" of either the OWL or HFS–related faults. Reidel et al. suggested that the HFS reflects the eastern margin of a piece of old continental craton (centered around the "HF" – Hite Fault – on the map) that has slipped south; Kuehn attributed 80 to 100 kilometers of left-lateral displacement along the HFS (and significant vertical displacements). The interaction of the Wallula and Hite Fault systems is not yet understood. Past the Hite Fault System the OWL enters a region of geological complexity and confusion, where even the trace of the OWL is less clear, even to the point where it has been suggested that both the topographic feature and the Wallula fault are terminated by the Hite fault. The original topographic lineament as described by Raisz is along the scarp on the northeast side of the Wallowa Mountains. However, there is a sense that the trend of the faulting in that area turns more to the south; it has been suggested the faulting associated with the OWL takes a large step south to the Vale Fault Zone, which connects with the Snake River Fault Zone in Idaho. Both of these lines introduce a bend into the OWL. The Imnaha Fault (striking towards Riggins, Idaho) is more nearly in line with the rest of the OWL, and in line with the previously mentioned gravitational anomalies that run into the continent. Which ever way is deemed correct, it is notable that the OWL seems to change character after it crosses the Hite Fault System. What this says about the nature of the OWL is unclear, although Kuehn concluded that, in northeastern Oregon or western Idaho, it is not a tectonically significant structure. Wallowa terrane As described above, the trace of the OWL becomes faint and somewhat confused between the Blue Mountains and the margin of the North American craton (the thick orange line on the map, just beyond the Oregon—Idaho border; the dashed line on the diagram below). This is the Wallowa terrane, a piece of