22 PROCEEDINGS OF TKE GEOLOGICAL SOCIETY. [NoV. 20, 



and does not occur as one homogeneous mass, like the ordinary lavas 

 of Etna, but in gigantic ovoidal masses, articulating one with another. 

 It rests on the outer flank of the cone, formed principally of volcanic 

 8Cori86 which have been altered by the effect of the fumarole of the 

 volcanic current, which, however, it is impossible to describe satis- 

 factorily, or to trace to its termination, in consequence of the ground 

 being in an advanced state of cultivation, and modified by the con- 

 struction of the more outlying dwelling-houses of Paterno, which 

 ^extend on that side of the hill to the extreme point. 



The other stream extending to the S.W. is different. The branch 

 which forms the Eock of Calacala — so called in Sicilian dialect on 

 account of the great steepness of the lava — extends in length 

 about 55 metres ; it presents a front of about 25 metres, is very 

 compact in the centre, and shghtly scoriform on the lower surface, 

 very much so on the upper ; it has an average thickness of about 

 3 metres, has an inclination of 36°, and rests on the volcanic 

 conglomerate, containing rounded pebbles of sandstone and clay 

 which have been altered by the action of the fumaroles of the 

 lava itself. This conglomerate forms part of the outer flank of the 

 cone. The other branch, which flows to the south, has not pre- 

 served its characteristic features so completely ; but neither of these 

 two branches of the volcanic stream reaches the base of the cone, 

 nor can their continuation be traced in the plain below ; which proves 

 that the lava did not extend beyond the side of the cone ; and the 

 base, which was formed of loose fragmentary materials, having been 

 carried away by the action of water, it has partly fallen down, the 

 upper portion of it still remaining in situ. 



This volcanic cone, even though it may have been denuded by the 

 action of water, nevertheless still affords a large quantity of fragment- 

 ary materials. At the Garden of the Capu chines, in which the crater 

 formerly existed, the scorise are of a black colour, with a slight reddish 

 tinge, very cellular and fragile ; there also occur metamorphosed pre- 

 existing sedimentary rocks. Scoriae are found in great abundance 

 along the Strada della Consolazione, under one of the ridges of the Bock 

 of St. Peter (and near the Church of St. Mark), which originally 

 belonged to the inner side of the cone, being found in immediate 

 proximity to the doleritic excrescence, and in a state of compact vol- 

 canic agglomeration, owing to the pressure of the overlying materials 

 which formed the outer flank ; whilst the materials which are seen 

 metamorphosed by an arm of the lava-stream near the Eock of Cala- 

 cala, those of the Strada della Consolazione to the south of the rock, 

 and those which are seen on the old road leading to the Salinelle, to 

 the north of this same mass of rocks, are a portion of the fragmentary 

 materials which formed the outer flank of the volcanic cone of Paterno, 

 which are still liable to removal, and in great measure have been 

 carried away by the action of rain-water and the Eiver Simeto, which 

 is constantly extending, with the materials which it carries along 

 with it, the plain of Catania. 



The rocky elements which constitute the fragmentary portion of 

 this cone are as follows : viz., doleritic scorioc, more or less altered ; 



