1871.] BE OKITEBA- — GEOLOGY OF JIALAGA. Ill 



mood to visit the Torcal, and hope that soon some ahler pen may do 

 full justice to its merits. 



As soon as our first impression had subsided, we began to speculate 

 upon the causes which had made the rocks assume such a fantastic 

 shape. We aU agreed that it must have been an eflFect of denuda- 

 tion ; in what particular way, however, we could not determine, 

 although we were inclined to ascribe it to an ancient glacier : this 

 opinion appeared to acquire some support when we found, on our 

 descent, some rocks detached and separated a long way from the 

 general mass, which we considered to be erratic blocks carried 

 down by the action of ice. However, not being satisfied with 

 this conclusion, and desiring to study the phenomena of the place 

 with more attention, some of us returned there ; and by starting 

 before daybreak from Antequera we were able to remain several, 

 hours on the Torcal, and had more time for observing the form 

 and composition of the rocks. 



In order to convey to you the best idea that I can of these forma- 

 tions, I shall begin with the plain of Antequera, which, in our rapid 

 excursions through it, we considered to belong to the Tertiary period. 

 The soil of the southern part of the city consists of a dark blue 

 and compact limestone, in a semicrystalline state, Avhich is over- 

 lapped on the northern side by a coarse and fragile rock, also 

 calcareous, with a certain mixture of sand, seeming to me to be 

 analogous to the " Calcaire grossier" of the Paris basin. This stra- 

 tum dips to the south ; its thickness is rather considerable — I believe, 

 reaching twenty or thirty yards. It contains many fossils, prin- 

 cipally the casts of an Area, which are very abundant. In the same 

 valley, in a place called Castillon, about thi-ee miles west of Ante- 

 quera, at the site of an ancient Roman town named Singilia, I have 

 found many fragments of a beautiful marble, entirely composed of 

 shells of Foraminifera—l believe, of the same kind as that which 

 Sir Charles Lyell describes in page 301 of the sixth edition of his 

 ' Elements,' under the name of Miliolite limestone. I had no oppor- 

 tunity of ascertaining the position of the blocks from which these 

 fragments were detached ; they were wrought remains of ancient 

 buildings ; but, considering their abundance, I came to the conclu- 

 sion that their quarry could not be far off. We have also in this 

 neighbourhood the same Miliolite limestone, in concretion with an- 

 other calcareous stratum, containing many NummuUtes (said also to 

 be found near Antequera, although I have not met with them 

 myself) ; and it is probable that both may belong to the same period, 

 and that this may be either the Middle or the Lower Eocene. I see 

 this is also the opinion of M. de Vemeuil ; for in his map he classifies 

 the plain of Antequera as " Tertiaire iuferieure," although he does 

 not seem to have found any Nummulites ; for that portion of his 

 map does not contain the sign which indicates their presence. 

 Between Antequera and the Torcal there is another calcareous 

 formation, containing many forms of Gryplicea ; it is above the blue 

 limestone, and of very limited extent. 



The Torcal rises abruptly from the plain of Antequera, its north- 



