"For we are the Ancients of the earth," wrote Tennyson, echoing a sentiment expressed by Francis Bacon centuries before: "These times are the ancient times, when the world is ancient, and not those which we count ancient ordine retrogrado, by a computation backwards from ourselves."
Beneath the fertile undulating fields of Meath and Munster, and the rich marshy bogland of our central plain, there lies an underlay of solid rock. In places it breaks through, and there is little else: this happens, for example, on the Burren in Co Clare, whose nakedness moved one Cromwellian general, mindful of his trade, to remark that here was not "water enough to drown a man, nor trees to hang him from, nor even enough earth in which to bury him".
Under most of the country lie layers of sedimentary rock, the limestone of the central plains and much of Connacht, and the sandstone of the Cork and Kerry mountains. These were laid down beneath the shallow seas that once covered this land; the compressed remains of animals and plants, and grains of sand precipitated to the ocean bottom.
Elsewhere is igneous rock which, as its name suggests, had its origins in fire; the basalt of Antrim and the Giant's Causeway, and the granite of the Wicklow mountains, Donegal and Connemara originated from hot molten material that, aeons ago, surged up from seething cauldrons in the bowels of the Earth.
Have you ever wondered about granite? Has it troubled you exactly what it was that melted underground, and why it felt obliged to bubble upwards to the surface? Have you scratched your head about when this Stygian fountain first appeared, and when it ended, and worried if it might occur again? Have you looked at a lump of granite rock and asked yourself "what stuff `tis made of, whereof it is born"?
If you answer "Yes" to any of these questions, you may be interested in a talk by Dr Padraig Kennan at 6.30 p.m. in the RDS this evening. Dr Kennan will be familiar to many television viewers as the presenter, a year or two ago, of a six-part RTE documentary, Written in Stone , which gave a general account of the geology of Ireland.
His topic for this, the 4th annual John Jackson Lecture, jointly organised by the Royal Dublin Society and the Royal Irish Academy, is more specific: it is "Granite - a Singular Rock", and it should tell you all you might ever wish to know about this interesting substance. Enter, with due reverence and decorum, through the Members' Door of the RDS, Ballsbridge.