1852.] PRATT — GEOLOGY OF CATALONIA. 271 



sandy limestone ; all these beds contain fossils, which appear to be of 

 the Miocene period. The lower beds are highly inclined, of a hard 

 crystalline structure, contain large masses of jasper, and appear 

 to have been acted upon by heat, although no igneous rocks are seen. 

 They are interstratified with thin beds of white clay and fuller's earth. 

 The limestone beds, which contain numerous fossils, and have not been 

 similarly acted upon, become nearly horizontal on the upper part of 

 the hill and on approaching the plain which lies between it and the 

 granite ridge behind Barcelona. The stratified alluvium which covers 

 the plain in nearly horizontal beds, rises several hundred feet on the 

 sides of the two hills which bound it, and has been disturbed in 

 the same degree with the beds upon which it lies ; particularly so 

 on the granite ridge, which penetrates it in several places. It appears, 

 therefore, probable that the elevation of these hills has taken place 

 subsequently to the deposition of this alluvial deposit. In several 

 deep fissures which cross the plain, granite is seen forming its base. 

 The granite reaches the north bank of the Llobregat, andisseenno more 

 except at a few points just above the surface on the other side of the 

 river. On each side of this river, about two miles from its mouth, 

 the red sandstone becomes considerably developed, covering the hills 

 to a considerable thickness, and extending to the north-west as far as 

 Montserrat. This is one of the most magnificent mountains in 

 Spain ; it attains the height of above 6000 feet, and is composed of 

 numerous layers of both fine and coarse sandstone, alternating with 

 thick conglomerate-beds. The red sandstone extends also to the 

 south-west, covering the ridges of hills which extend as far as the Ebro. 



To the north-west, and nearly parallel to this ridge of granite, ■ 

 schist, limestone, and sandstone, there is a plain about ten miles 

 wide, with an irregular and undulating surface. It is bounded 

 by another ridge which rises near Gerona, and extends nearly to 

 the north bank of the Llobregat. Near Gerona the latter ridge 

 has been much disturbed, and separated into several low hills by 

 the uprising of granite and more recent igneous rocks. It is 

 entirely composed of tertiary deposits, and all that part of it near 

 Gerona and upon which the city is built is extremely nummulitic. 

 To the north of the city, these beds rise to the height of about 300 

 feet, lying upon the red sandstone above described, but soon sepa- 

 rating from that deposit, they form a series of low hills, which gra- 

 dually sink into the plain five or six miles east of Gerona. Other 

 low ridges, which run nearly parallel to these at a very short distance, 

 are composed of the same beds, almost entirely nummulitic ; and there 

 are others beyond, farther west, containing numerous tertiary fossils 

 also of the Eocene period. These low ridges have been considerably 

 disturbed by the upheaval of large masses of lava, containing much 

 olivine, and have every character of a recent origin. In many places 

 this lava is seen beyond the hills, and forms extensive, perfectly flat, 

 and almost naked plains. 



Still further west, at the distance of nearly eight miles, another 

 much higher ridge rises nearly parallel to those already described. It 

 cent ainsmany tertiary eocene fossils, but without Nummulites. This 



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