Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/253

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1869.]
BAILY-IRISH GRAPTOLITES.
159

numerous specimens examined in connexion with my duties on the Geological Survey of that country.

Commencing with the south of Ireland, the first place to be noticed is in the county of Waterford, on the banks of a stream called the Dalligan river, five miles N.E. of Dungarvan, where dark grey argillaceous shales occur full of the small diverging Graptolite, Didymograpsus sextans, Hall; they were first discovered at this place by Mr. Charles Galvan, of the Geological Survey. In the list of fossils, appendix to 'Siluria,' 1867, the geological range of this species is limited to the Llandeilo group of rocks. Proceeding towards the city of Waterford, at Lady Elizabeth's Cove, in Tramore Bay, highly inclined black slates dipping 80° N.E. may be seen on the shore just below high-water mark, penetrated by a greenstone dyke and in close proximity to rocks containing a profusion of fossils of Caradoc-Bala age; these slates are of a dull earthy character, much impregnated with pyrites, and yielded the following species:—


  • Graptolithus Hisingeri, Carruthers (= Sagittarius).
  • *[1]Didymograpsus sextans, Hall.
  • Cladograpsus gracilis, Hall.
  • Diplograpsus pristis, Hisinger.
  • Climacograpsus bicornis, Hall.
  • Dicranograpsus ramosus, Hall.

together with the following reticulated and many-branching forms, the affinities of which to Graptolites I agree with Mr. Carruthers in considering to be very doubtful,—

  • Dictyonema, sp.
  • Callograpsus elegans or Salteri.
  • Dendrograpsus flexuosus or diffusus.

At a second locality, in Tramore Bay, Diplograpsus pristis occurred in grey slate, associated with Trilobites.

A little north-west of the town of Waterford, on the left bank of the river Suir, are cliffs 150 feet in height, composed for the most part of unfossiliferous Silurian flags and slates, penetrated by masses of Greenstone Porphyry; at the base of the cliff, which is here called the Bilberry rock, a mass of much-jointed and finely laminated dark grey slates, highly inclined, and in some parts stained red and yellow, were to be seen when I visited the place some months since; as, however, it, with the flaggy beds immediately adjoining, was being quarried away, this fine Graptolite-locality may soon disappear, or has perhaps already disappeared. These slates are crowded with well-defined, although much compressed Graptolites; and as the layers separate with great facility, good specimens were readily obtained. The species are few, but abundantly repeated, Diplograpsus pristis being the most numerous: it occurs with prolonged axis and proximal termination. The next species in point of numbers is a diverging form, the initial process being well shown in some examples which I believe to be identical with the species Dr. Nicholson figures[2], and refers to Didymograpsus (Graptolithus) flaccidus, Hall. Mr. Carruthers has described this species under the name of Didymograpsus elegans, doubting its identity with Hall's species; I agree with him

  1. The asterisks prefixed to species indicate their comparative abundance.
  2. Annals and Magazine of Natural History, ser. 4, vol. i. p1. 3. fig. 14.