Mr. Bryce on the Geological Structure of Roseneath. 119 



the features of the landscape.* It crosses nearly through the middle 

 of the remarkable and very picturesque dell, which intersects the 

 peninsula from Campsail Bay to Kilcreggan in a direction nearly 

 north-east and south-west. Thus, in external aspect, and in the 

 nature of its rocks, this southern portion is isolated from the rest; it 

 consists of a single hill of a depressed conical form, having a smooth 

 outline, and extending in gentle and fertile slopes to the water's 

 edge on three sides. Here, as in other places, the soil formed by the 

 decomposition of the sandstone contrasts most favourably with that which 

 rests upon the cold retentive clays of the coal formation on the one side, 

 and the old slate rocks on the other. The series exhibits but its 

 lowest members — conglomerates, coarse sandstone, and finely laminated 

 red sand, irregularly disposed. The base of the conglomerate is coarse 

 red sand ; and the imbedded fragments are granite, porphyry, quartz, 

 and various kinds of slate ; the three former are very much rounded, the 

 latter have lost their angularity, and present elliptic forms. The origin of 

 these is to be looked for in some near district of the Grampians, where 

 such varieties exist, and which we know were elevated and exposed 

 to the action of mechanical forces prior to the epoch of the old red sand- 

 stone; the quartz and slate pebbles are from the adjoining strata. 



The contact of the sandstone and slate is nowhere seen. In the 

 western part of the cliffs at Portkill Bay, the two rocks approach very 

 close, the sandstone dipping at a small angle towards the nearly vertical 

 slate ; and in Campsail Bay a considerable space of flat beach intervenes, 

 concealing the contact. The line of junction passes near the Saw-mill, 

 and across the upper part of the fields, which slope down from the 

 northern edge of the plantation crowning the heights on the south side of 

 the great hollow or dingle. 



On the south coast of the peninsula the sandstone dips for a short dis- 

 tance towards the south ; the dip then changes, and continues in other 

 parts to be between west and south-west, at an angle of about 15" to 20°. 



e. Proofs of Elevation. 



10. In the paper referred to in Art. 1. the phenomena which indicate 

 a change of level in the sea on the shores of Bute were so fully stated 

 that it is unnecessary to enter here at any length into the subject, the 

 evidences being of the same character. A well defined terrace exists along 

 most parts of the shores of the peninsula. It is but faintly impressed upon 

 the bold rocky shores (Art. 3) in the northern part. But from Culeport 

 southwards to Kilcreggan it is extremely well marked. The breadth 

 varies from ten or twenty yards, to one hundred, or even more. It is 

 terminated inland by a perpendicular cliff, twenty to forty feet high, com- 

 posed of slate rocks much worn and often hollowed into caves. In some 



• "Uosncath " is said by some to mean in the Gtelic language, "the little dell 

 or dingle ;" and that the name was given to the whole from this peculiar feature. 

 Sec New Statistical Account uuder " Roseneath parish, DumbartoDshirc." 



