290 W. H. HOBBS — GUADIX FORMATION OF GRANADA, SPAIN 



terial, but its role would appear to be secondary to the cloudbursts and the 

 resulting torrents of the rainy season. 



Such an alternation of conditions as is indicated by the material of the 

 Guadix formation is found today only in arid regions of high relief, 

 where the rare but violent storms develop the torrent and the playa lake, 

 and where the wind plays an important part in transporting the surface 

 material. The climate within the province of Granada is today semi- 

 arid — the fertile Vega of Granada being an oasis, which only accentuates 

 the surrounding aridity. 



Age of the Deposits 



As already indicated, Miocene fossils have been found in the Block 

 formation of von Drasche, and as has here been shown, torrential de- 

 posits are forming today in the valley of the Darro and elsewhere. It is 

 probable that the Guadix formation includes beds extending without 

 noteworthy interruption from the Miocene to the present. That similar 

 conditions have prevailed from even earlier times might be inferred from 

 the occurrence of a conglomerate of Triassic age at the base of Alquife 

 hill, which is located on the exact border of the Guadix formation and at 

 the foot of the Sierra Xevadas. This conglomerate includes angular 

 boulders of iron ore whose dimensions are sometimes measured in feet.* 



Torrential Deposits of southern Italy 



Deposits remarkably similar to those of the Guadix formation border 

 much of the mountainous coast of the Italian peninsula and Sicily. 

 Above Eeggio, in Calabria, blocks of granite two feet or more in their 

 largest dimensions are found associated with similar blocks of several 

 other crystalline types as lenticular forms within deposits of sand, gravel, 

 and finer material, all of which has clearly been derived from the 

 Ualabrian Apennines immediately to the east. The bedding of these de- 

 posits is for the most part nearly horizontal, though angles as high as 

 30 degrees were observed. The topography of these deposits, wherever 

 dissected, is that of the "bad lands" — the type for rain erosion. Such 

 deposits may be seen to even better advantage to the westward of Messina, 

 in Sicily, on the road to Castellaccio. 



The intermittent streams (torrcnti or fiumare), which are so char- 

 acteristic of southern Italy, have dissected the deposits. These valleys 

 are wide at their mouths, with broad, flat floors, which ascend at ex- 

 tremely low but ever increasing grades toward their heads, where the 

 slope I'ises abruptly like a wadi to form an amphitheater. On these 



* William H. Hobbs : Mining in Spain. The Mining World, vol. 24, 190(5, pp. 109-110. 



