272 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 5, 



ridge also has been much disturbed and elevated by the upheaval of 

 masses of granite and porphyry of considerable extent ; indeed the 

 whole district between this point and the base of the Pyrenees has 

 been so much disturbed, that it requires considerable time to map its 

 geological features correctly. On proceeding to the south-west from 

 Gerona the country is also much disturbed in several places, but to a 

 more limited extent, as far as the neighbourhood of Vich. On ap- 

 proaching this place, the tertiary ridges become very much developed, 

 and extend with little interruption, except at a few points, to the 

 neighbourhood of the Llobregat, forming in several places hills of 

 considerable height. Beyond this river a considerable change takes 

 place, but the ridges may be traced onwards to near Villa Franca and 

 Tarragona. A httle to the south-west of Vich the main ridge is 

 divided, for the distance of a few miles, by a narrow but deep valley ; 

 the portion to the east is composed of granite hills, rising in one place 

 to the height of about 2000 feet ; in other parts, however, the granite 

 is much lower, and is composed of an arkose, having a very compact 

 character, and formed of sharp-edged masses of granite of a very 

 different character from the great mass. It is covered in several 

 places by a limestone, highly inclined, bearing evidence of igneous 

 action, and containing a very few of the same fossils (Encrinite stems) 

 as those in the limestone overlying the high ridge, previously described. 

 The second portion of the ridge is composed of numerous calcareous 

 and sandy beds, differing much in character, but apparently of the 

 same age, as nearly all contain Nummulites. The beds are highly 

 inclined where they approach the granite, and become nearly hori- 

 zontal at a short distance from it. They have a thickness of from 

 700 to 1500 feet. Some of the beds contain numerous fossils, of 

 the same species as those observed in the hills near Gerona, and very 

 similar to those found at Biarritz in France. This ridge is divided 

 in several places by very deep narrow valleys or chasms, which give 

 vent to numerous powerful streams. On the north-west side it is 

 covered by a bed of calcareous rock containing numerous specimens 

 of a large Cerithium, very similar to the C. giganteum of the Paris 

 basin, and descending into the plain which lies between this ridge 

 and another distant about ten miles. This plain is much less 

 disturbed than the other, and the ridge which bounds it to the west 

 is lower, and of a later tertiary period, probably the Miocene ; the 

 majority of the fossils, however, are pecuUar to it. It extends to the 

 south-east, beyond Montserrat, and thence to the north-west of Villa 

 Franca. 



To the south-west of the Biver Llobregat, the character of the 

 country changes considerably, for although a succession of plains 

 and ridges still continue as far as the Ebro, yet they are considerably 

 modified, becoming much more irregular in form and proportion. 

 The ridge near the coast to the south of the mouth of the Llobregat 

 is much wider, more irregular in its composition, and terminates 

 almost entirely beyond Villa Nueva. It is composed chiefly of very 

 thick calcareous beds, partially covered by the red marly sandstone 

 already noticed. The fossils are very rare and obscure in their 



