ANNIVEKSAKY ADDKESS OF THE PKESIDENT. IxXXvil 



then describes the successive changes and phenomena which took 

 place during this period, tending to the deposition and formation of 

 the different beds ; he also alludes to the great changes which the 

 older rocks themselves, which form the Diluvium, have undergone 

 during this period. The quartz and quartzites are generally only 

 changed into rolled pebbles, although some blocks of quartzite 

 are to be seen with traces of a conical structure, as if they had 

 been violently struck with a heavy blow ; this is shown on the out- 

 side by circular fissures which penetrate into the interior, expand- 

 ing more and more from the centre ; the feldspar and Silurian slates 

 are reduced to an argillaceous state. Even the blocks of granite 

 have so completely lost their coherence that they can be cut through 

 with the spade or mattock. The same thing occurs with the lime- 

 stone, and even with gneiss, which is generally so little liable to de- 

 composition. One of the most remarkable diluvial phenomena in 

 this district is, that the calcareous rocks, after losing their coherence 

 by the operation of diluvial agents, and being scattered amongst the 

 sands and clays, did not become mixed up with them, but remained 

 quite isolated, although reduced to a soft earthy state. Yery few 

 cases of hard rock occur in the Quaternary beds, although the author 

 observed a few small bands or patches of conglomerate or pudding- 

 stone cemented together by a calcareous or ferruginous matrix. 

 Calcareous tuff is very scarce. There are very few caverns of any 

 importance in the limestone rocks in this district. There is only 

 one worth noticing, called the Cueva del Eeguerillo, in the Ponton 

 de la Oliva ; it contains numerous stalactitic and stalagmitic forma- 

 tions. No bones, ancient or modern, have been found in it ; but as 

 yet no excavations have been made in the stalagmitic bottom, al- 

 though in the neighbouring provinces of Segovia and Guadalajara 

 there are several caverns from which objects of great interest have 

 been collected. The author does not say what they were. 



The paleeontological discoveries in this Quaternary formation are 

 extremely poor in Spain, in the province of Madrid almost nil ; 

 tusks and bones of an elephant were found by M. Graells near San 

 Isidro. This probably belongs to a new species ; for the author states 

 that Dr. Falconer, who saw the remains in Madrid, at once declared 

 that they did not belong to either Eleplias primigenius, or E. afri- 

 canus, or E. armenianus. Another lower jaw with three molar teeth, 

 also found near- San Isidro, probably belongs to Cervus elaphus. 

 Cervus tarandus has not yet been found in Spain, and it is remarkable 

 that these two species are never found inhabiting the same locality. 



The author concludes with an account of some flint hatchets found 

 in the diluvium of San Isidro, as far back as 1850, in the gravel and 

 below the beds containing the elephant bones, and vrith some re- 

 marks on the antiquity of man, on the recent and vegetable soils, 

 and on the remains of pre-historic times. He feelingly alludes to 

 the difiiculties he has had to contend with in the total absence of all 

 geological observations on this district before he undertook his task ; 

 and every geologist will sympathize with his last words — " I always 

 started from Madrid with my knapsack and hammer cheerful and 



