784 
the hills or to the westward of the parent rocks few of these pebbles 
are found, proving, the author says, the eastwardly direction of the 
transporting currents. 
_ Yhe natural drainage of the country is remarkably simple. The 
greater portion of the small quantity of rain which falls in Central 
and Upper Egypt is absorbed by the deserts and collected in natural 
basins like the Oases ; the remainder is partly carried off by the 
great, evaporation, and partly conducted to the Red Sea by transverse 
eracks on the eastern side of the anticlinal axis, or to the valley of 
the Nile by similar cracks on the western flank of that axis. The 
drainage of the Libyan desert is also effected through the valley of 
the Nile. The amount of water which escapes by these means is 
however so small, that the Nile throughout the last 1350 miles, or 
about one-half of its course, does not receive what may be termed a 
single tributary. 
Il. Formations.—The deposits of which Egypt consists, are ar- 
ranged by Mr. Newbold under the heads of, 1. hypogene rocks with 
argillaceous schist, 2. breccia di verde, 3. lower sandstone, 4. marine 
_ limestone, 5. upper sandstone, 6. post-pliocene deposits, 7. drift, 
8. volcanic rocks, 9. alluvial accumulations, 10. sand-drifts. 
I. Hypogene Rocks.—These constitute a small portion of Egypt. 
Between the Red Sea and the Nile, Mr. Newbold observed them only 
in the latitude of Kossier (26° 8’) resting against granite in highly 
inclined or curved strata, and forming an east and west zone 30 miles 
in breadth. He is of opinion that the same beds may probably range 
south by east, hypogene rocks appearing at Gebel Zerbara (lat. 
24° 30'). Ina northerly direction they have been traced to fhe cata- 
racts, resting on granite.” 
Gneiss, with thin “veins” of marbie, usually constitutes the low- 
est strata, which are overlaid conformably by micaceous, talcose, 
hornblende, and argillaceous schists and quartzite. Dykes or masses 
of basalt, greenstone, porphyry, and serpentine are associated with 
the whole series. All the hypogene rocks assume a crystalline cha- 
racter near the granite or trap, the gneiss and hornblende schist be- 
coming garnetiferous and abounding in actynolite, both crystallized 
and compact; the taleose schist also passes into potstone and ne- 
phrite with iron pyrites, as at Mount Baram; the micaceous schists at 
Gebel Zerbara yield emeralds, avanturine, hzmatitic, and specular 
iron ore; and the clay-slate changes into basanite or flinty slate. 
2. Breccia di Verde—The argillaceous slate is overlaid confor- 
mably, in lat. 26° 8’, by the celebrated breccia di verde. . This rock 
presents thick-bedded strata, which become more horizontal on re- 
ceding from the granite, and is composed principally of angular and 
rounded fragments of greenstone, gneiss, porphyry, argillaceous and 
flinty slates, serpentine and marble, also sometimes of light green com- 
pact felspar and hypogene rocks, cemented by aslightly calcareous 
paste of various shades of green and purplish red. No fossils have 
yet been noticed in the rock. The cliffs composed of this breccia 
_ rarely exceed 200 feet in height above the level of the desert. 
3. Lower Sandstone—Above the breccia di verde occurs a sand- 
