28 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [DeC. 9, 



the entire length of the Nasb valley, is strewn with masses of a hard 

 black haematite, in angular blocks with sand-scratched surfaces, hav- 

 ing a somewhat scoriaceous look. This api^ears to have been con- 

 fused by travellers at different times with the actual copper-slags 

 that exist in the same valley. Blue and green carbonate of copper, 

 and a little calamine, are also found in the sandstones on the same 

 horizon. 



Old Mines. — Several small pits have been opened upon the iron 

 and manganese bed, both at liasb and on the top of the adjoining 

 table-land. As far as can be made out from Arab accounts, none 

 of these are of any great age, the most important dating from 

 about sixty years back. Several camel-loads of pyrolusite are said 

 to have been taken from a pit on the hill, and sent to Cairo as an 

 experiment, the general belief being that it was sold for use in co- 

 louring the eyelids (kohll) instead of galena. If this was the purpose 

 to which it was really applied, we can easily understand why the ex- 

 periment was never repeated. On the western side of the Kasb Yalley 

 there are indications of old workings, besides modern levels driven a 

 short distance into the side of the hill ; but their exact nature is not 

 quite clear, as they have become choked up with rubbish, ]3artly 

 from the fall of the roof, but more from the sand and wash of the 

 valley brought down by the rains. 



At Wady Khalig, a tributary of Wady Baba, about four miles 

 below j^asb, the iron and manganese bed has been extensively exca- 

 vated by the old miners. Here it occurs under the form of a soft 

 schistose white marl, variegated with green and red patches, and 

 contains small strings of earthy-brown iron-ore, with a little blue 

 and green carbonate of copper, and the smallest joossible spots of 

 copper-glance or perhaps indigo copper-ore. The old workings ex- 

 tend about 120 yards along the face of the hill. JSTear the surface 

 the roof has fallen in manj' places, leaving a large irregular cavern, 

 with several openings to the day. Deeper under the hill, where tlie 

 rock has been better protected from the weather, the height of the 

 excavation is about 5 feet, and the whole of the ground has been 

 removed, with the exception of a few small pillars at distances of 

 about 50 feet apart. The walls and pillars are covered with small 

 chisel- or gad-marks, apparently made with a tool about | or |- of 

 an inch in breadth. The distance to which the workings extend 

 from the face of the hill is about 40 yards ; but this cannot be de- 

 termined exactly, as there is a considerable deposit of muddy sand 

 on the floor, washed in by the rains (the bed having been followed 

 on the dip), which has no doubt completely filled up the lowest part 

 of the mine. In some places the roof is supported by stone and 

 mortar walls ; but these are probably of newer date, having been put 

 up to render the cavern secure for the purpose of a dwelling or a 

 store-house. 



There are no inscriptions or any other guide to the probable date 

 of these workings; but it is evident, from the extraordinarily 2">oor 

 character of the ore, that they must belong to a very early period, 

 when metals were of nearly uniform value^ owing to their produc- 



