266 SIR WILLIAM DAWSON, C.M.O., LL.D., F.R.S., 



Among these are some relating to a subject which im- 

 presses itself very strongly on a geological traveller in the 

 Nile Valley, namely, the various rocks and minerals used 

 by the Egyptians from very early times, the purposes to 

 which they were applied, and the manner in which they 

 were quarried and worked. I made large collections to 

 illustrate these points ; not, however, I may be excused for 

 saying, by defacing monuments, but by collecting broken 

 fragments lying on old sites, and by visiting quarries and 

 natural exposures. Egypt affords unlimited material of this 

 kind to a lithological collector, without detriment to existing 

 works of art, and much may also be obtained from the 

 people, who quickly understand the value both of rock 

 specimens and fossils when pointed out to them, and who 

 cannot fabricate these in the manner of clay scarabs and 

 other imitations of antiques. 



The present notes may be considered supplementary to 

 what is stated in the work above referred to. 



1. Granitic, Dioritio, and Gneissic Rocks. 



To these groups belong a large part of the monumental 

 stones of Egypt ; and from the First Cataract and the hilly 

 ranges east of the Nile they were transported to every part 

 of the country, even to the shores of the Mediterranean and 

 the neighbourhood of the Isthmus, and this not in small 

 blocks but often in great masses much more weighty than 

 any used, in modern architecture or sculpture. For this, no 

 doubt, the navigable water of the Nile and its canals, and 

 the variations of its level in the inundations, afforded great 

 facilities. 



The most important of all these rocks is the celebrated red 

 granite of Syene, so generally employed in the greater 

 Egyptian monuments. I have given detailed descriptions of 

 this rock and its varieties in the Appendix to Modern Science 

 in Bible Lands, and may merely say here that it is essentially 

 a holo-crystalline rock, often coarse-grained and consisting 

 mainly of orthoclase and plagioclase felspars, with a little 

 microline — associated with hornblende and quartz, the latter 

 usually in small quantity. When mica is present, it appears 

 to be biotite, and there are sometimes minute crystals of 

 apatite, sphene, and magnetite. 



The study of this rock in place at Assouan convinces me 

 that in regard to its mode of occurrence it is sometimes an 

 intrusive or indigenous granite, and sometimes a true bedded 



