The history of the two paintings is also ambiguous and thus not very helpful to scholars who have researched the question. Several ideas have been set forth, however, with inconclusive results (see Appendix for historical details).
The fact that attribution of the two works has been unresolved and the subject of such scrutiny throughout history suggests that new diagnostic means of determining authenticity are in order. A comparison of the representations of geological formations in the two paintings offers such means. It seems unlikely that the same person could have portrayed geological formations so accurately in the Louvre work and so incongruously in the National Gallery painting.