The points in the interior of the Libyan Desert of which the levels are fairly accurately known now number many hundreds, and with the exception of a large blank in the unexplored west, and another between the Nile and Merga in the Northern Sudan, they are fairly well distributed over the country. It therefore seemed to me to be worth while to make another attempt at a contoured map; for the levels now known (though still far too few for contours to be drawn with any great precision) might suffice for the construction of a map on a comparatively small scale and with contours at fairly wide intervals; it was felt that a provisional map of this kind, besides affording at least an approximate general view of the relief, might help towards the solution of one or more of the problems which I have mentioned above. I commenced by sketching in the contours at 100-metre intervals on the original sheets of the 1:500,000 map of Egypt, a revised edition of which is in preparation. They were then reduced to the million scale, and afterwards still further reduced, with additions from my own recent observations around Owenat, Gebel Kissu, and Merga, from Hassanein Bey’s records of his journey between Jalo and El Fasher, from the altitude-data obtained by the Anglo-French Boundary Commission in the Sudan,[2] and from the maps of Prince Kemal el Din’s expedition of 1926 to Owenat and Sarra Well,[3] to form the map following p. 96. The attempt has, I think, fully justified itself, and more than fulfilled the hopes that were entertained concerning it. Probably the feature that will first strike the attention on glancing at the contoured map is the series of depressions below sea-level stretching westward from near Cairo to Jarabub. The following table gives a list of the principal of these depressions, with the approximate extent of the areas lying below sea-level, and also (where known) the depths below sea-level of their deepest parts. Where the lowest part is covered by a lake, the depth shown is that of the water-surface, not that of the lake-bottom: _Approximate area _Approximate _Depression._ below sea-level depth of deepest in sq. kiloms._ part below sea in metres._ Wadi Natrun 220 23 Faiyum 700 45 Wadi Rayan 280 43 Qattara (including Moghara, 18,000 134 Qara, and Tebaghbagh) Sittra (including Timata) 300 33 Bahrein (including Nuemisa) 150 15 (?) Watiya 70 15 Areg 60 25 Siwa (including Maasir and 800 17 Maraqi)