270 SIR WILLIAM DAWSON, C.M.G., LL.D., F.R.S., 



It would be extremely interesting to examine the quarries 

 from which it was obtained, and to ascertain, if possible, the 

 date when they began to be worked. 



Diorite of many varieties — black, greenish, black with 

 white blotches or mottled with black and white — forms great 

 dykes and eruptive masses in the crystalline district of Upper 

 Egypt, and was always and deservedly esteemed by the 

 Egyptians. I have elsewhere remarked that, as diorite is 

 one of the best materials for the formation of polished stone 

 hatchets, it must have very early attracted attention ; and its 

 toughness, lustre, and susceptibility to a good polish must 

 have indicated it as a material for sculpture. Accordingly, it 

 is applied to a great variety of uses, from colossal statues 

 down to platters and trays. A large proportion of the finest 

 Egyptian statues are cut in diorite. 



A dark grey granite has also been employed. It differs 

 from the diorite in containing a little free quartz, and in 

 having orthoclase felspar ; but hornblende is usually its chief 

 constituent. I have observed this black granite in a door- 

 way at Karnak, in loose pieces on the site of a temple at 

 Gizeh, in a sarcophagus at Thebes, in one of the Apis sarco- 

 phagi at Sakkara, in statues of Bast, and in a figure of 

 Nectanebo and a hawk from Pithorr. in the British Museum. 



True diorite occurs in the Rosetta Stone and the Great 

 Scarabseus and several sarcophagi in the British Museum,* 

 in the Pithom Sphinxes now at Ismailia, and in the Hyksos 

 Sphinx and the fish offerers in the Gizeh Museum, and a 

 great number of statues. One of Rameses II in the 

 British Museum is a stone from the junction of red granite 

 and diorite, and thus consists of two distinct lands of rock. 



2. Basalt with Olivine. 



The term basalt has been used in a somewhat loose sense 

 by writers on Egypt, apparently to designate any dark 

 crystalline or subcrystalline rock. Some of the objects 

 designated by this name prove to be dark-coloured horn- 

 blendic granites, others are diorites. One rock to which the 

 name very properly applies, occurs plentifully in loose chips 

 on some parts of the pyramid plateau, as if portions of the 

 temples or tombs which have disappeared from that area 

 had been composed of it. A chip from this place has been 

 sliced and has been examined for me by Mr. Frank D. 

 Adams, of McGill University, with the following results: — 



•Professor T. Rupert Jones, F.K.S., in Proc. Geol. Association, vol. viii. 



