Ch. XXXI.] PLIOCENE VOLCANOES. 669 



distance is the Pyrenees, which are to the north of the spectator, 

 and consist of hypogene and ancient fossiliferous rocks. In front of 

 these are the fossiliferous formations (No. 4), which are in shade. 

 Still nearer to ns the hills 2, 3, 5, are volcanic cones, and the rest of 

 the ground on which the sunshine falls is strewed over with volcanic 

 ashes and lava. 



The Fluvia, which flows near the town of Olot, has cut to the 

 depth of only 40 feet through the lavas of the plain before men- 

 tioned. The bed of the river is hard basalt; and at the bridge of 

 Santa Madelina are seen two distinct lava-currents, one above the 

 other, separated by a horizontal bed of scoriae 8 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 de Tosca," the upper 

 part of which is scoriaceous, and covered* with enormous heaps of 

 fragments of. basalt, more or less porous. Between the numerous 

 hummocks thus formed are deep cavities, having the appearance of 

 small craters. The whole precisely resembles some of the modern 

 currents of the 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 volcanoes are as entire as those in the 

 neighborhood of Naples, or on the flanks of Etna, One of these, 

 called Montsacopa (No. 3, fig. 719), is of a very regular form, and 

 has a circular depression or crater at the summit, It is chiefly made 

 up of red scoriae, undistinguishable from those of the minor cones of 

 Etna. The neighboring hills of Olivet (No. 2) and Garrinacla (No. 5) 

 are of similar composition and shape. The largest crater of the 

 whole district occurs farther to the east of Olot, and is called Santa 

 Margarita. It is 455 feet deep, and about a mile in circumference. 

 Like Astroni, near Naples, it is richly covered with wood, wherein 

 game of various kinds abounds. 



Although the volcanoes of Catalonia have broken out through 

 sandstone, shale, and limestone, as have those of the Eifel, in Ger- 

 many, to be described in the sequel, there is a remarkable difference 

 in the nature of the ejections composing the cones in these two 

 regions. In the Eifel, the quantity of pieces of sandstone and shale 

 thrown out from the vents is often so immense as far to exceed in 

 volume the scoriae, pumice, and lava ; but I sought in vain in the 

 cones near Olot for a single fragment of any extraneous rock ; and 

 Don Francisco Bolos, an eminent botanist of Olot, informed me that 

 he had never been able to detect any. 



Volcanic sand and ashes are not confined to the cones, but have 

 been sometimes scattered by the wind over the country, and drifted 

 into narrow valleys, as is seen between Olot and Cellent, where the 

 annexed section (fig. 720, p. 670) is exposed. The light cindery 

 volcanic matter rests in thin regular layers, just as it alighted on the 

 slope formed of the solid conglomerate. No flood could have passed 

 through the valley since the scoriae fell, or these would have been for 



