1861.] GEMMELLAEO — YOLCANIC CONES. 23 



clay in every state of metamorphism, passing even into thermantitc ; 

 and pebbles of sandstone (gres), some of which have been roasted and 

 fall to pieces with the slightest touch, while others, on the contrary, 

 have ptissed into the state of quartzite. 



The country around Paterno, is, from north to east, entirely covered 

 ■with the pp'oxenic lavas fi'om Etna ; whilst the alluvial soil which 

 forms the plain of Catania is exposed to the south and shows a hori- 

 zontal stratification, as the fi-eshwater calcareous tuif, which overlies 

 it, rests on the west side of the rock. This recent calcareous tuff 

 contains many fossil plants and land-shells, amongst which can bo 

 made out Bidimus decoUatus, Brug., HelLv vermimdata, L., Heliv 

 aspersa, Miill., &c., — species which are still living and abundant in the 

 neighbourhood. 



Volcanic Cone of Motta (Sta, Anastasia). — The village of Motta 

 (Sta. Anastasia) is also built on the remains of a volcanic cone. It is 

 elevated about 813 Paris feet (Hoffmann) above the level of the sea, 

 distant about thirteen miles fi"om the present axis of Etna, and offers 

 on a smaller scale the same phenomena as we have observed at 

 Paterno. 



The sides of the Eock of ITotta (Sta. Anastasia), from west to north, 

 are in connection with the pre-existing sedimentary formations; but 

 the village being almost entirely built on it, it is impossible to de- 

 scribe it satisfactorily. The doleritic nucleus is almost perpendicular 

 on the south side, the lower portion of which consists of large and 

 irregular prisms, which fi'om below upwards, for about 25 metres, 

 converge to the centre, whilst in the upper portion the dolerite loses 

 this character and becomes amorphous. To the S.E. it is connected 

 with great masses of conglomerate, of volcanic scoriae, clay, and 

 pebbles of sandstone (gres), altered like those of Paterno. On the 

 east side, this nucleus is cut through by a road, which has exposed 

 between the articulated joints of one of its outer ridges a great mass 

 of clay, with sand and pebbles of grit, altered and contorted by the 

 pressure of the doleritic nuclens, and which at the time of its intru^ 

 sion were also carried up. On the S.AY. side the same amorphous 

 nucleus is also seen, and in connection with great masses of volcanic 

 conglomerate which overlie it from the base up to the rugged crests. 



In this eruption the lava-stream also issued from the upper part 

 of the cone. It issued from the side to the west of the JSiorman 

 Tower, and flowed towards the S. W., and can be traced as far as the 

 Church della Immacolata. This lava, however, is less clearly made 

 out than that of Paterno, being cut through and broken away in many 

 places for the construction of the houses and roads of the upper part 

 of the village ; it is nevertheless easily made out at the commence- 

 ment, and its course can be traced, being very ccUular on its upper 

 surface, compact in the centre, and about 3 metres thick in some 

 places. 



The fragmentary materials consist of scoriae, clay, sand, and pebbles 

 of sandstone (gres), altered by the igneous action of the volcanic rock, 

 and which, being here and there in contact with the doleritic nucleus, 

 constitute the foundations of the internal sides of the cone. The 



