300 DEFILE OF AIN TAESIL. ch. xii 



entered the singular defile which, as well as the village, 

 is known by the name Ain Tarsil. It has evidently been 

 formed by erosion from the limestone strata which dip 

 slightly towards the south. The surrounding country 

 here shows a hilly undulating surface, unbroken by any 

 marked inequalities ; but the stream, though dry in 

 ordinary weather, has cut a trench from two to three 

 miles in length, and from thirty to fifty feet in width, 

 between steep walls of rock about equal in height to the 

 width of the trench. 



M. Balansa, the only traveller who is known to 

 have passed through this defile, must have been more 

 hurried than we were, as he does not speak of the numer- 

 ous rare and local plants which grow upon the rocks, 

 most of them, indeed, the same that we had found on the 

 rocks about Seksaoua. But he could not avoid being 

 struck by the singular excavations in the rock, evidently 

 used at some remote period for human habitation, which 

 extend at intervals along both sides of the defile. In some 

 cases there may have been a natural recess in the rock, 

 afterwards artificially enlarged ; but the majority appear 

 to be altogether the work of human hands ; and in most 

 of them, where the entrance had become difiicult owing to 

 the breaking away of pieces of rock from the edge, this 

 was afterwards made good by building up a bit of loose 

 wall of irregular blocks of stone. The height of the 

 entrance does not exceed four feet, and is often less. The 

 most singular point about these dwellings is the fact that 

 they are all near the top of the cliff, where the rock is 

 nearly vertical, in positions that cannot now be reached 

 without a ladder, or other artificial assistance. It might 

 be suggested that since these prehistoric dwellings were 

 abandoned, the work of erosion has deepened the trench, 

 and thus increased the difficulty of access ; but unless we 

 suppose that during tlie same period the climatal con- 

 ditions have been profoundly modified, this seems a highly 

 improbable explanation. As far as we could afterwards 



