Ch. XXXI.] 



YOLCANOS OF CATALONIA. 



535 



Section above the bridge of Cellent. 



a. Scoriaceous lava. 

 ft. Schistose basalt, 

 c. Columnar basalt. 



ri. Scoriae, vegetable soil, and alluvium. 

 e. Nummulitie limestone. 

 j. Micaceous grey sandstone. 



'gneous and marine formations ; and it is interesting to remark that in 

 this, as in other beds of pebbles occupying a similar position, there are 

 no rounded fragments of lava ; whereas in the most modern gravel-beds 

 of the rivers of this country, volcanic pebbles are abundant. 



The deepest excavation made by a river through lava, which I ob- 

 served in this part of Spain, is seen in the bottom of a valley near 

 San Feliu de Pallerdls, opposite the Castell de Stolles. The lava there 

 has filled up the bottom of a valley, and a narrow ravine has been cut 

 through it to the depth of 100 feet. In the lower part the lava has a 

 columnar structure. A great number of ages were probably required 

 for the erosion of so deep a ravine ; but we have no reason to infer that 

 this current is of higher antiquity than those of the plain near Olot. 

 The fall of the ground, and consequent velocity of the stream, being in 

 this case greater, a more considerable volume of rock may have been 

 removed in the same time. 



Section at Castell Follit. 



A. Church and town of Castell Eollit, overlooking precipices of basalt. 



B. Small island, on each side of which branches of the river Teronel flow to meet the 



Fluvia. 



c. Precipice of basaltic lava, chiefly columnar, about 130 feet in height. 



d. Ancient alluvium, underlying the lava-current. 



e. Inclined strata of secondary sandstone. 



