Vol. 65.] SOUTH OF THE OASIS OF KHARGA. 53 



no evidence that the dykes ever pierced that sandstone. The 

 conclusions advanced by Sir J. William Dawson, in his ' Modern 

 Science in Bible Lands ' (1888), had been fully justified by the 

 work of the surveyors who acted under Capt. Lyons. The whole 

 region must have been upraised since Cretaceous times, and hence it 

 was not surprising to find a certain amount of confusion at the 

 contact between the Nubian Sandstone and the cr3 r stalline rocks, 

 confusion which the Author had apparently taken for "intrusion. 



Dr. Tball said that he had spent a few days at Aswan, and had 

 examined junctions of the Nubian Sandstone with the underlying 

 crystalline rocks between Aswan and Philse. He had with him at 

 the time of his visit the admirable map and memoir issued by the 

 Egyptian Geological Survey, in which Dr. Ball had recorded the 

 result of his detailed work in the region, and he could confirm the 

 accuracy of Dr. Ball's description of the relation between the two 

 groups of rocks. He (the speaker) had not a shadow of doubt that 

 the Nubian Sandstone had there been deposited upon a crystalline 

 complex, and he did not believe that there was a shred of evidence 

 in that region of the intrusion of any granitic rock into the Nubian 

 Sandstone. But the important part of the Author's paper was that 

 in which he recorded original observations in a comparatively 

 unknown region : such observations were always welcome. The 

 high dips in the sedimentary rocks, on which the Author laid great 

 stress as evidence of intrusion of the granite, might be, and probably 

 were, due to earth-movements similar to those that the Author had 

 so well described at Abu Roash, in which also Cretaceous rocks were 

 involved. Contact-metamorphism had been mentioned, and, if it 

 were positively proved, the Author's case would be made out so far 

 as the special district was concerned; but, even then, the result would 

 not affect the well-established conclusions arrived at by previous 

 observers in the region of the First Cataract and elsewhere. 



The Author, iu replying, remarked that he was well aware that 

 the sandstones described as Nubian were in some parts of the 

 country of considerably earlier age than Upper Cretaceous. There 

 seemed little doubt, however, that in the area described the sand- 

 stones were of the same age as those in the northern part of the 

 Oasis, that was, Campanian. 



He wished to point out that he himself had for many years (and 

 he had been actively engaged in geological work in Egypt for 12 

 years) accepted the view still held by his former Survey colleagues, 

 that the granites were in all cases older than the Nubian Sand- 

 stones ; and that it was not until after he had visited the district 

 in question, and carefully weighed the whole of the published 

 evidence relating to other parts of the country, that he found 

 himself forced to dissent from the commonly-held view and admit 

 that some of the cases of intrusion cited by Schweinfurth, Russegger, 

 and other early observers, might not after all have been incorrect. 

 He did not, however, wish to insist, as seemed to be assumed 

 by Prof. Hull and Mr. Hudleston, that the granites in all parts of 

 the country were intrusive — he had indeed definitely stated the 





