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Such appears to be the fact, and I shall therefore conclude with the Arenig beds my enumeration of the Silurian formations in Great Britain, and proceed to say something of their foreign equivalents, before treating of rocks older than the Silurian.
"Arenig Vawr," they replied, or something like it. Presently meeting four men I put the same question to the foremost, a stout, burly, intelligent-looking fellow, of about fifty. He gave me the same name as the women. I asked if anybody lived upon it. "No," said he, "too cold for man." "Fox?" said I. "No! too cold for fox." "Crow?" said I. "No, too cold for crow; crow would be starved upon it."
We have already seen that in the Arenig or Stiper-Stones group, where the species are distinct, the genera agree with Silurian types; but in these Tremadoc slates, where the species are also peculiar, there is about an equal admixture of Silurian types with those which Barrande has termed "primordial."
The felspathic lavas, with their associated beds of tuff and breccia, rise into some of the grandest mountain crests of North Wales, such as those of Cader Idris, Aran Mowddwy, Arenig and Moel Wyn. A similar series is also represented in Ireland, ranging from Wicklow to Waterford, forming a double group of felstones, porphyries, breccias, and ash-beds, with dykes of basalt and dolerite.
I subsequently remembered that Arenig is mentioned in a Welsh poem, though in anything but a flattering and advantageous manner. The writer calls it Arenig ddiffaith or barren Arenig, and says that it intercepts from him the view of his native land. Arenig is certainly barren enough, for there is neither tree nor shrub upon it, but there is something majestic in its huge bulk.
The Lower Silurian has been divided into, first, the Bala Group; secondly, the Llandeilo flags; and, thirdly, the Arenig or Lower Llandeilo formation. Orthis tricenaria, Conrad. Orthis vespertilio, Sowerby. Shropshire, N. and S. Wales. Two-thirds natural size.
Tired after a while with turning over the pages of the trashy "Cavalier" I returned the volumes to their place in the corner, blew out one candle, and taking the other in my hand marched off to bed. The Bill The Two Mountains Sheet of Water The Afanc-Crocodile The Afanc-Beaver Tai Hirion Kind Woman Arenig Vawr The Beam and Mote Bala. AFTER breakfasting I demanded my bill.
It has been conjectured that this carbonaceous matter may be due in great measure to large quantities of imbedded animal remains, for the number of Graptolites included in these slates was certainly very great. In Great Britain eleven genera and about 40 species of Graptolites occur in the Llandeilo flags and underlying Arenig beds.
Around the flanks of Muilrea, beds of purple quartz-felstone with tuff are interstratified with the Upper Silurian grits and slates. Lower Silurian Period. Volcanic action was developed on a grand scale during the Arenig and Caradoc-Bala stages, both in Wales and the Lake district, and in the Llandeilo stage in the South of Scotland.
Professor Sedgwick had described, in 1843, strata now ascertained to be of the same age as largely developed in the Arenig mountain, in Merionethshire; and the Skiddaw slates in the Lake-District of Cumberland, studied by the same author, were of corresponding date, though the number of fossils was, in both cases, too few for the determination of their true chronological relations.
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