Rev. 8. 8. Dornan — Geology of Basutoland. 57 



introduced into the oases from Persia, where underground aqueducts 

 or ' kai'eez,' for the transference of water from one locality to another, 

 have from an early date heen extensively employed. The immense 

 amount of time and labour which must have heen expended can hardly 

 be realised without actually exploring the excavations themselves, but 

 it may be remarked that at Um el Dabadib the two main carrying 

 channels, with their subsidiary branches, measure several kilometres 

 in length, and are cut almost throughout in hard sandstone rock, the 

 tunnels being moreover connected at frequent intervals with the 

 ground surface above by vertical air shafts, likewise excavated in the 

 solid rock; one of the latter which I descended measured 130 feet in 

 depth. 



It is difficult to believe that the supplies of water obtained from 

 these sandstones were commensurate with the time and labour involved 

 in the construction of the necessary collecting tunnels, but that enough 

 water was obtained to enable fairly large colonies to exist is evident 

 from the traces of former villages and cultivated areas. After the 

 withdrawal of the Romans these outlying districts were abandoned 

 and the subterranean aqueducts gradually silted up. Some few years 

 ago one of the main tunnels at Um el Dabadib was completely cleaned 

 out, and when I visited the place in 1905 the discharge at the mouth 

 of the aqueduct was about 30 or 35 gallons a minute.^ 

 {To be concluded in the March Number.) 



II. — jS"otes on the Geology of Basutoland. 

 By the Eev. S. S. Doenan. 

 rpHE rocks composing Basutoland belong to the Stormberg Series of 

 \_ the Karroo Sj-stem. They cover a much larger area than 

 Basutoland, extending into the Orange River Colony on the west and 

 north, on the south and east into Cape Colony and Natal, and, I am 

 informed, across the Vaal into the Transvaal. The area is thus not 

 less than 45,000 square miles. The whole of that part of the Orange 

 River Colony known as "the Conquered Territory," east of a line 

 drawn from Thaba 'J^chu to Yrede, is occupied by the whole or 

 portions of these rocks. 



The average thickness of the rocks is as follows : — 



Designation. Thickness of feet. 



Recent and superficial accumulations ... ... ... 20-40 



/■ (1) Volcanic Beds "... 600-4000 



Stormberg ) (2) Care Sandstone 150-400 



Series. Ws) Eed Beds 300-500 



\ (4) Molteno Beds (base not seen) ... ... ... 600 exposed. 



^ Ball visited the locality in 1898 before the tunnel described above had been 

 cleaned out, and is responsible for the rather fantastic theory that it led to another 

 inhabited oasis to the north of the escarpment (op. cit., pp. 31 and 76). The same 

 writer further remarks (p. 82) : " It is worthy of note that, with the exception of 

 the Eoman work near Ain Um Dabadib and a line of bricked manholes near Gennah, 

 no traces of under.a'round watercourses, such as occur so abundantly in Baharia Oasis, 

 are to be seen in Kharga." As a matter of fact, however, there is hardly a district 

 in northern Kharga where extensive underground aqueducts do not occur, and they 

 far exceed in magnitude anything found in the oasis of Baharia. 



