72 Colonel Silvertop on the Lacustrine Basins of 



southern portion of the basin, shews that it has been broken 

 through or furrowed in different places by currents descending 

 from the primitive district to its south, and the streams now 

 flowing through the consequent fissures, taking a north-westerly 

 direction, finally terminate, before leaving its area, in the river 

 Genii. These fissures, of which one of the boldest and most 

 characteristic is seen close to Alhama, contracted in the vicinity 

 of the mountains, subsequently expand into little valleys of de. 

 nudation. In one of these, beginning to open out immediately 

 below Alhama, the observations were made which belong to the 

 section A ; those referrible to B were partly made in the last 

 mentioned fissure or ravine which confines the rivulet above Al- 

 hama, and partly in the neighbourhood of the villages of Arenas 

 and Jayena. 



A. The horse-road from Alhama to the town of Loja de- 

 scends the little valley of denudation which commences near 

 the former village, and is watered by the rivulet of the same 

 name ; and, at the distance of about two miles, crosses a small 

 ravine * whose bed and banks a^e formed of secondary num- 

 mulite limestone. This rock is divided into strata from two 

 inches to a foot thick, dipping at a small angle towards the 

 W.NW., and is no doubt connected below with the great mass 

 of the same limestone which constitutes the boundary of this 

 part of the basin towards the south. These strata are succeeded 

 in immediate superposition, on the left bank of the ravine, by a 

 few strata of calcareous sandstone, identical with that observed 

 at the entrance into Alhama by the Velez-Malaga road. In a 

 subsequent short ascent no rock is seen, but it is crowned by a 

 low escarpment of coral limestone in thick horizontal strata, bor- 

 dering a little flat upon which a farm-house and a few cottages 

 have been built. From this point the road begins to ascend a 

 hill of considerable elevation, named El Majar de en Medio, 

 which intervenes between the left bank of the rivulet of Alhama 

 and the bounding ridge of secondary limestone towards the south. 

 The rising undulating surface presents a light soil, which, 

 after rain, becomes what is termed sticky, the whole of it being 

 under cultivation, and producing great crops of wheat and bar- 



• This ravine terminates in the rivulet of Alhama, at about two miles 

 distance from the point in it alluded to in the text. 



