O;.DI;R PLIOCKM: PF.RIOD. [Ch. XIV. 



map. The greatest number of perfect cones are in the imme- 

 diate neighbourhood of Olot, some of which are represented in 

 the frontispiece, and the level plain on which that town 

 stands has clear] v been produced by the flowing down of many 

 lava-streams from those hills into the bottom of a valley, 

 probably once of considerable depth like those of the surround- 



ing country. 



In the frontispiece an attempt is made to represent by colours 

 the different geological formations of which the country is 

 composed. The blue line of mountains in the distance are the 

 Pyrenees, which are to the north of the spectator, and consist 

 of primary and ancient secondary rocks. In front of these are 

 the secondary formations described in this chapter,, coloured 

 grey. 'Different shades of this colour are introduced, to express 

 various distances. The flank of the hill, in the foreground, 

 called Costa de Pujou, is composed partly of secondary rocks 

 and partly of volcanic, the red colour expressing lava and 

 scoriae. 



The Fluvia, which passes near the town of Olot, has only 

 cut to the depth of forty feet through the lavas of the plain 

 before mentioned. The bed of the river is hard basalt, and at 

 the bridge of Santa Madalena, are seen two distinct lava- 

 curreiits, one n'-ove the oilier, separated by a horizontal bed 

 of scoriai eight feet thick. 



In one place, to the south of Olot, the even surface of the 

 plain is broken by a mound of lava, called the ' Bosque dc 

 Tosca/ the upper part of which is scoriaccous, and covered 

 with enormous heaps of fragments of basalt more or less porous. 

 Between the numerous hummocks thus formed, are deep cavi- 

 ties, having the appearance of small craters. The whole precisely 

 resembles some of the modern currents of Etna, or that of 

 Come, near Clermont, the last of which, like the Bosque de 

 Tosca, supports only a scanty vegetation. 



Most of the Catalonian volcanos are as entire as those in the 

 neighbourhood of Naples, or on the flanks of Etna. One of 

 these, figured in the frontispiece,, called JMontsacopa, is of a 



