In parts of its course, this second band appears to run so perfectly parallel with the bedding of the strata between which it lies that the observer would readily believe it to be a part of the same series of deposits, and might therefore regard it as affording good evidence of volcanic action contemporaneous with the formation of these deposits. A transverse section of the bed, where thus apparently conformable, is shown in Fig. 197. [Illustration: Fig. 197.--Section of a bed of Volcanic Breccia in the Carboniferous Slate; White Bull Head, County Cork. 1 1. Sandstones and shales; 2. Breccia.] [Illustration: Fig. 198.--Volcanic Breccia invading and enclosing Carboniferous Slate, White Bull Head.] Further examination, however,reveals that this seemingly regular sequence is entirely deceptive. At various points the breccia abruptly truncates the sandstones, and involves large pieces of them, as shown in Fig. 198 A. At other places, the lower side of the breccia, or what would be its base if it were a regular bed, cuts out the strata and sends veins into them (B). And the same structure is visible, on its upper side, or what would be its top (C). It is clear that these highly-inclined bands of breccia are not contemporaneous with the deposition of the Carboniferous Slate, but have been introduced into their position at some time subsequent not only to the deposition, but to the disturbance and elevation of the strata. The peninsula of White Bull Head is crossed by several other similar bands. On Black Bull Head, also, together with abundant felsitic and doleritic intrusions, a similar breccia or agglomerate is to be seen. In some parts it is compact in texture with spheroidal flinty lumps, and weathers somewhat like a nodular felsite. This variety ends off rather abruptly to the north, but swells out southward, and then runs out into a high, narrow headland, in which it contains asbestos, as well as rounded crystals of hornblende. It has here disrupted the shales and sandstones, and near the junction is largely composed of fragments of them, the strata themselves being jumbled, bent, and broken up. The only semblance of a neck-like mass of this volcanic fragmental material occurs on White Bull Head, where one of the bands expands about the centre of the ridge, and is there full of large blocks of grey sandstone. The breccia appears to have filled fissures which have been opened between the bedding planes of the highly tilted strata, giving rise to long narrow dyke-like intercalations. We have seen that among the Carboniferous volcanic phenomena such dyke-like masses of agglomerate occasionally present themselves in the vents both of the plateaux and the puys.