Hugh J. L. Beadnell — Floiving Wells, Kliarga Oasis. 103 



strata, the water is derived from the surface-water sandstones, the 

 explanation may lie in the general east and west dip, resulting in 

 a difference of level of the sandstones here and in adjacent districts — 

 a difference which may be sufficient to furnish the necessary working 

 head, which, as has been suggested by Cridler & Johnson, may be the 

 only essential requirement for an artesian flow.' 



Artesian-ivater Sandstones. 



The source of the great majority, if not of all, the flowing wells 

 of the oasis is the group of sandstones underlying the " impermeable 

 grey shales." Needless to say, the beds of the series are nowhere 

 visible to the eye, but judging by the samples obtained from the 

 bores put down under my supervision during the last two years they 

 do not differ in general characters from the sandstones just described. 

 Throughout the area over which our operations have extended, no 

 well-defined or persistent argillaceous bands have been met with, 

 though the deepest bores have been carried to a depth of 122 metres 

 (400 feet) below the junction of the sandstones, with the confining 

 shales above. The beds vary considerably in coarseness and porosity, 

 in hardness, and in the amount of cementing material between the 

 individual grains of the rock, all of which characters have a marked 

 influence on their capacity as water-carriers. Thin seams of lignite, 

 frequently associated with bands of iron pyrites, testify to the 

 conditions under which these beds were originally laid down. 



The Artesian Wells. 



As no very reliable data concerning the few native wells which 

 have been sunk in recent times are available, it will be more satisfactory, 

 in describing the wells themselves, to confine our attention to those 

 which have been drilled on the headquarters area during the last 

 two years and of which accurate and reliable records have been 

 preserved. 



The area around headquarters is one of the few large districts 

 entirely devoid of old wells and traces of ancient cultivation. 

 A combination of circumstances appears to have led the ancients to 

 regard this area unfavourably : firstly, the general elevation is com- 

 paratively high, meaning small flows from wells of ordinary depth ; 

 secondly, the 'soil' is heavy, necessitating a considerable expenditure 

 of time and labour to bring it into good growing condition ; and 

 thirdly, and probably most important of all, the presence of a copious 

 supply of surface water, which would have greatly hampered, if not 

 made impossible, the old system of well-sinking. 



It may be assumed, therefore, that owing to the entire absence 

 of both ancient and modern wells the water- sandstones of this district 

 were practically fully charged at the time the first bore was sunk. 



The junction of the artesian-water sandstone with the grey shales 

 above is usually fairly abrupt, the first flowing water being obtained 

 as soon as the bore strikes the top of the sandstone. Although 



' A. F. Cridler & L. C. Johnson, "Underground Water Eesources of Mississippi" : 

 Water Supply and Irrigation Paper No. 169, United States Geological Survey 

 publications. 



