1871.] DE OKTTEBA GEOLOGY OF MALAGA. 113 



could not anywhere perceive the slightest distortion. We concurred 

 in opinion that it had been denuded after attaining its high level. 



The mountain-chain of which the Torcal forms a part extends 

 in a western direction for about thirty miles. After leaving the plain 

 of Antequera it takes the name of " Sierra del Yalle de Abdalagis," 

 ending a little to the west of the place crossed by the Malaga and 

 Cordova Railway, named the " Tajos del Gaitan." In this spot the 

 river Guadalhorce has not only excavated a very deep and narrow 

 ravine, but it has actually pierced through an enormous mass of 

 rock at least 800 feet high, giving a further proof of the highly 

 disintegrable character of the rock. The scenery here is also very 

 wild and grand ; and no traveller who passes through this defile can 

 be wholly free from a feeling of awe and admiration. The colour of 

 the compact limestone in these parts of the chain is white, having 

 little or no admixture of iron. However, this rock is everywhere to 

 be seen superposed upon the Oolite. The Jurassic strata which con- 

 stitute the mountainous districts to the south and west of Eonda may 

 belong to the same period, as well as those which exist in this 

 neighbourhood, about two miles west of the town, constituting 

 the quarries of St. Telmo, mentioned in Professor Ansted's memoir ; 

 these rocks, though devoid of fossils, have a marked similarity to 

 those which constitute the Tajos del Gaitan. The corroboration of 

 these views, however, must be the result of a careful and consci- 

 entious study, which I have not undertaken. 



Note. — This paper was accompanied by photographs of Ammonites 

 obtained from the compact limestone of the Sierra del Valle de Ab- 

 dalagis, and of one from the Sierra de la Chimenea. These Am- 

 monites are all of Jurassic age, and probably from the middle and 

 higher members of that group of rocks. Some of the specimens 

 represented are far too imperfect for identification ; but Mr. Etheridge, 

 to whom they have been submitted, refers four of them to Amm. 

 Achilles, L'Orb. (PL Y. fig. 1), and two others to Amm. per armatus, 

 Sow., one of which closely resembles the var. catena, D'Orb. (fig. 3). 

 The remainder cannot safely be identified. Of the species repre- 

 sented in fig. 2, there are photographs of two ages. 



EXPLANATION OF PLATE V. 



(Figures about half the natural size.) 



Fig. 1. Ammonites Achilles, D'Orb. 



2. Ammonites, sp. 



3. Ammonites perarmatus, Sow., var. catena, D'Orb. 



Discussion. 



Prof. Ansted remarked that the condition of the Torcal was similar 

 to that prevailing in many other limestone districts, and was pro- 

 bably due to subaerial denudation. 



Mr. W. W. Smyth mentioned that he had lately had an opportunity 

 of examining, at Cadiz, a collection of fossils formed by Mr. Mac- 

 pherson in that district, which also contained specimens of Ammo- 



VOL. XXVII. PART I. I 



