d'oRTJETA GEOLOGY OF MALAGA. 493 



could see the Javaluna conglomerate cropping out ; and as we could 

 not at that moment perceive any other formation, we imagined that 

 they belonged to those rocks. On this second occasion I satisfied 

 myself that they are imbedded in the sandstone, and that those we 

 found on the road had been carried thither by the action of water. 

 Another common fossil of the Kimmeridge Clay is also found in this 

 formation, namely Ostrea deltoidea, but not so abundantly as the 

 OrypJicea. 



I think that the verification of these two well-known fossils will 

 leave little doubt that the siliceous formation on which the Torcal 

 sandstone reposes corresponds with that which in England consti- 

 tutes the second division of the Upper Oolite ; and consequently 

 the rocks which cover it, if they belong to the Jurassic group, must 

 either fall into the same division, or perhaps belong to the Portland 

 series. 



In case there should still be anj^ doubt about the Jurassic character 

 of these fossils, and any one should be inclined to believe that they 

 have more resemblance to Cretaceous forms, I will mention another 

 fact which has lately come to my knowledge. By inquiring among 

 the inhabitants of the villages, I have ascertained the existence in 

 the " Tajos del Gaitan " of a calcareous deposit, whiter and of softer 

 texture than the above-mentioned marbles, over which it has been 

 described to me as lying unconformably. It contains fossils, and 

 one form in particular, which must be Terehratula di-pliya. M. de 

 Yerneuil seems also to be aware of the existence of this deposit ; for 

 in his map he marks the " Etage Tithonique " as existing in this 

 locality. My friend Mr. J. Macpherson, of Cadiz, writes to me that 

 he has found the above-mentioned Terehratula in some deposits in 

 close connexion with limestones of acknowledged Jurassic origin. I 

 am not aware that this fossil has ever been found in any stage but 

 that called Tithonic, the position of which has been the subject of 

 much discussion ; but even if it corresponds with any member of the 

 Cretaceous group, it can only be with the oldest known division 

 of the Neocomian. 



Having concluded the subject of classification, I will now present 

 some reflections on the peculiar condition of the Torcal. It has been 

 generally assumed that the condition of the Torcal is due to sub- 

 aerial denudation after it had attained its high level ; but consider- 

 ing the great extent of the phenomena and the different waj's in 

 which rocks can be influenced by rain, frost, heat, dryness, or other 

 physical causes, in my late expedition I again carefully examined 

 the district, in order to see if I could observe any signs of subaerial 

 denudation, and reconcile myself to the idea that the Torcal had 

 been influenced by the same physical causes as the surrounding 

 regions, and merely acted upon more powerfully on account of its 

 central position, the horizontality of its strata, or some other pecu- 

 liarity in its condition. My observations, however, have confirmed 

 my previous opinion that the agent which modelled the fantastic 

 rocks of the Torcal was of a quite different nature from that which 

 shaped the rest of the chain. 



