46 



slates, and their own peculiar forms, much of the picturesque beauty 

 of this favourite watering-place is due. Thus the ridge lying be- 

 tween the coast and the valley of Hafton lake, owes its elevation and 

 bold outline to an outburst of igneous rocks, which have induced a 

 very decided change upon the slate along the planes of contact. It 

 consists of crystalline greenstone, of a different type from that of the 

 dikes common on the coast, the structure being slaty and the horn- 

 blende in excess. It is from 60 to 100 yards wide, and ranges from 

 near Hunter's Quay, across the highest part of the ridge, trans- 

 versely to its length, appearing along the summit in a series of conical 

 hummocks, with deep hollows between ; and thus presenting a bold 

 picturesque outline when viewed from the low grounds in the neigh- 

 bourhood. It is interrupted by the Hafton valley, but is resumed 

 on its western side, and attains its greatest altitude in Dunloskin 

 hill, which rises prominently above the surrounding slopes, strikingly 

 relieving their monotonous outline. Westwards, for about half, a 

 mile, it is seen in other rocky eminences, but its farther extension 

 in this direction was not traced. The ridge is not seen intersecting 

 the coast, which is everywhere occupied by the slate rocks ; so that 

 it seems to terminate before reaching the shore. Owing to the 

 metamorphic character which has been impressed upon the adjoining 

 slaty beds, it is difficult to determine the precise limits of the 

 plutonic rock ; near the contact the slate breaks under the hammer 

 into very compact four-sided prisms. 



In a similar manner, the high ground dividing the East and West 

 Bays, and projecting beyond the general line of coast, has acquired 

 its strikingly picturesque aspect from a great dike of basalt which 

 traverses it. The castle hill consists of this dike, and of slate borne 

 up with it, and adhering to it. By contact with the dike, the slaty 

 structure is effaced ; the rock has been fused and reconsolidated into 

 a compact flinty slate, closely resembling basalt; crystals are de- 

 veloped along the boundary, and bands of different colours are dis- 

 posed parallel to the sides of the dike. The width is about 100 feet, 

 and the bearing W.N.W. The G-antock rocks are exactly in the 

 line of bearing, but were found to consist of very hard slate. On 

 the opposite coast, however, near Ardgowan, a dike of the same 

 width and direction occurs, which may be the continuation. 



Near Inellan the slates are covered by patches of old red sand- 

 stone and its associated cornstone, as already mentioned. 



