. Manual of the geology of Ireland. OrctrvitcmeOahbro + +, Felstcne AA* BakedShale v.: \ Tu/r Shalef&GritsAlluvuun- Map of Baked Rocks round vent of eruption, Owenduff, County Wexford. off from the mass of eruptive rock as to the steam, gases,and such like products of vulcanicity given off during thetime the eruptions were taking place, which percolatedthrough the adjoining rocks and altered them, prior to thetime that the present granitic rocks consolidated. Thatan alteration similar to that now described, and due solely Metamorphic Rocks. 185 to the gases and suchlike products of vulcanicity
. Manual of the geology of Ireland. OrctrvitcmeOahbro + +, Felstcne AA* BakedShale v.: \ Tu/r Shalef&GritsAlluvuun- Map of Baked Rocks round vent of eruption, Owenduff, County Wexford. off from the mass of eruptive rock as to the steam, gases,and such like products of vulcanicity given off during thetime the eruptions were taking place, which percolatedthrough the adjoining rocks and altered them, prior to thetime that the present granitic rocks consolidated. Thatan alteration similar to that now described, and due solely Metamorphic Rocks. 185 to the gases and suchlike products of vulcanicity can takeplace, is proved in various localities where tracts of similarparoptetic rocks occur, although there are no protrusions oferuptive rocks associated with them. * The vents or pas-sages of the Plutonic outburst are also found higher up inthe formation among the lower rocks of the Ballymoneyseries. Here, since many of the altered rocks were origi-nally felspathic and basic tuffs or tuffose rocks, the new. \iicus{SVvaZeJ - + 4 Choked Shales)?Hornstone. [_>< * xjeLitone Map of isolated patches of Hornstone and Felstone, Tigroney (Ovoca), County Wicklow. rocks are very puzzling; as these tuffs readily changed intorocks which are in places undistinguishable from felstones,eurites, and gabbros. These paroptetic rocks form numerous small tracts inSE. Waterford, in Wexford, and in Wicklow. In thelatter county those found in the vicinity of the Ovoca * It was probably an action of this kind that altered the Jurassic rocks atPortrush, County Antrim, as described in the chapter on the Mesozoic rocks. 186 Geology of Ireland. mines are very remarkable. Here, associated with theMineral channel, are detached masses which by most writershave been called felstones. Weaver, however, in hisdescription pointed out that some of them were hornstones,and that these, to all appearance, were originally each patch is abruptly cut off, as shown in theaccompanying map ; but in
Size: 1735px × 1440px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublishe, booksubjectgeology
