Numerous rocks in the Red Sea Hills and the Nile Valley were worked in Egyptian and Roman times for ornamental purposes; among them may be specially mentioned the purple imperial porphyry of J. Dokhan, the green breccia of Wadis Hammamat and Dib, the dolerite of Wadi Esh, and the hornblende granite of the first cataract. In modern times local granite was used throughout the Assuân dam and an Oligocene basalt is quarried at Abu Zabel and used for road-metal in the capital and other towns.
Old workings and mining camps are of common occurrence in many parts of the Eastern Desert and there is no doubt that considerable quantities of gold were extracted by convict labour. The quartz lodes traverse not only the metamorphic rocks but also some of the granites. Iron (hematite, limonite), copper (chrysocolla, copper pyrites) and lead (galena) bearing veins also occur, and turquoise, jasper and chrysolite are found in certain localities. Petroleum and sulphur occur sparsely near J. Zeit, and gypsum in large quantities in many parts of the country.
Phosphate deposits in the form of accumulations of bones, teeth and coprolites of fish in compact beds, have a wide distribution in the Eastern Desert, the Nile Valley and the southern oases, though these beds have not yet received the attention their importance deserves. Better known are the nitrate bearing clays which are so highly valued and largely used by the fellahin throughout the country. The chief horizons are the Esna shales and the underlying cretaceous clays, but disintegrated clays of every age are worked throughout the country, though their nitrate content may be very low and their salt content high; more prized still is the material from the middens marking the sites of ancient towns.
Natron (carbonate of soda) and salt are associated in considerable quantities in Wadi Natrun, and the latter is widely distributed in limited quantities throughout the country, the main supply being however obtained by evaporation from the shore lagoons along the coast of the delta. Rock salt of fine quality occurs in many localities, notably in the Eocene limestones three to four days east of Assiut.
APPENDICES
| Tables | Pages | ||
|---|---|---|---|
| A. | I. | Areas of the catchment basins of the Nile | [119] |
| B. | II. | Slopes of the Nile in its different reaches | [120] |
| C. | III and IV. | Velocities of the Nile in its different reaches | [121] |
| D. | V to X. | Distances of places on the Nile from each other | [123] |
| E. | XI and XII. | Details of observed discharges | [129] |
| F. | XIII to XXIII. | Observed discharges referred to gauges | [131] |
| G. | XXIV. | Mean discharges of the Nile tributaries in 1902, 1903 and 1904 | [139] |
| H. | XXV. | Maximum and minimum discharges in 1902 and 1903 | [141] |
| I. | XXVI. | Monthly discharges at Khartoum, Assuân and Cairo | [142] |
| J. | XXVII to XL. | Discharge tables for the different gauges on the Nile | [143] |
| K. | XLI to LII. | Detailed information about the Nile, Assuân to Cairo | [153] |
| L. | LIII to LXIX. | Gauges of the Nile and its tributaries | [167] |
| M. | LXX and LXXI. | Assuân and Cairo gauges, metres corresponding to pics | [209] |
| N. | LXXII and LXXIII. | Table converting cubic metres per day to cubic metres per second and vice versa | [211] |
| P. | LXXIV. | Bombay rainfall referred to the Assuân gauge | [213] |
| Q. | LXXV to LXXXI. | Meteorological data in the Nile Valley | [214] |
N.B.—In [Appendix L], the gauges are recorded in two different methods. If the fall or rise of water surface is gradual throughout the year, the gauges are recorded in five daily intervals. If, on the other hand, the rise and fall is gradual for the first four and last three months of the year, but the changes are abrupt in the remaining five months, the gauges are recorded in five daily intervals for seven months and daily for five months.