268 SIR WILLIAM DAWSON, C.M.G., LL.D., P.R.S., 



gists as anorthite rock or gneissic anorthosite. It occurs in 

 various parts of the Laureutiau districts of Canada, and 

 more especially in those portions held by Logan to be Upper 

 Laurentian. In Egypt, this rock first attracted my attention 

 as the material of a magnificent statue of Kephren, the 

 builder of the second pyramid, now in the Gizeh Museum. 

 In this statue the lines of black hornblendic matter which 

 mark the foliation are distinctly visible, especially on the 

 right side. I was informed by M. Emil Brusch Bey that 

 several similar statues in a broken condition had been 

 found, and was enabled, through his kindness, to obtain 

 some chips for examination. These were subsequently 

 studied by Dr. B. J. Harrington, and compared with the 

 analogous rocks of the Laurentian of Canada.* 



More recently, some new slices were cut and were 

 examined by Mr. F. D. Adams, whose description is as 

 follows : — 



" In the hand specimen, it cannot be distinguished from a 

 variety of anorthosite found at New Glasgow, P.Q., and else- 

 where in the Laurentian system of Canada. 



" When the slide is examined under the microscope, the 

 rock is seen to be very fresh, and to be composed essentially 

 of felspar with a very small amount of hornblende, which, in 

 one place, is intergrown with a little pyroxene. 



" Nearly one-half of the felspar grains show polysynthetic 

 striations, and are, therefore, plagioclase ; the remainder, 

 although occurring as untwinned individuals, show in almost 

 every case good cleavages, and a biaxial figure when cut 

 normally to an optic axis, and in appearance differ in no way 

 from the twinned grains. They are probably also plagio- 

 clase, since, as Hawes pointed out several years ago, the 

 plagioclase in Canadian anorthosite rocks frequently shows 

 no striations. 



" The hornblende is present in very small amount as 

 compared with the felspar, and occurs in irregular-shaped 

 grains. It is pleochroic in green and yellowish tints. No 

 quartz, iron ores, mica, or other minerals are present. 



" In the thin section, as in the hand specimen, it bears a 

 strong resemblance to many of our Canadian anorthosite 

 rocks." 



I have placed in the Redpath Museum a specimen of 



* Modern Science in Bible Lands, pp. 270, 573. 



