

IRELAND. 



IRELAND is bounded on the south, west, and 

 north by the Atlantic, and on the east by a 

 strait called, at different places, the North Chan- 

 nel, the Irish Sea, and St George's Channel 

 which separates it from Great Britain. The strait 

 is about 47 miles wide between St David's Head, 

 in Wales, and Carnsore Point, in Ireland ; about 

 55 between Holyhead and Dublin ; and 13 be- 

 veen Fair Head and the Mull of Kintyre, in Scot- 

 id. Ireland has a coast-line of not less than 

 2200 miles. It lies between lat. 51 26' and 55 21' 

 lorth, and between long. 5 20' and 10 26' west. 

 The island, according to Dr Clyde (School Geo- 

 graphy, by James Clyde, LL.D.) 'consists of a 

 central plain inclosed by mountainous districts, 

 except at the bays of Dublin and Galway, where 

 it reaches the shore in a considerable extent of 

 coast-line. This central plain would very nearly 

 coincide with a four-sided figure, having for its 

 ~aur corners the towns of Wicklow, Galway, Sligo, 

 and Dundalk. It occupies one-fourth of the 

 sntire surface of the island, and is so low that the 

 lighest point between Dublin and Galway is only 

 320 feet above the level of the sea. The principal 

 ranges in the mountainous districts separating the 

 central plain from the sea, are the Mourne Moun- 

 tains, in County Down ; the mountains of Antrim, 

 >nnected with which are the basaltic columns 

 lown as the Giants' Causeway ; Mount Nephin 

 and Croagh Patrick, in Mayo ; Macgillicuddy 

 "leeks, in Kerry, the highest peak of which, Carran 

 Tual (3410 feet), is the highest mountain in Ire- 

 land ; the Slievh Bloom Mountains, on the borders 

 of King's County and Queen's County; the Knock- 

 mele-down Mountains, between Tipperary and 

 Waterford ; and the Wicklow Mountains. The 

 central plain nearly inclosed by these mountains 

 is one immense deposit of limestone, overlaid to a 

 great extent by bog. Tullamore, in Queen's 

 bounty, is the centre of the bog region.' 

 The largest of these morasses is the Bog of 

 Hen, which stretches in a vast plain across the 

 entre of the island, or over a large portion of 

 Lildare, Carlow, King's and Queen's Counties 

 laving a summit elevation of 280 feet, in which 

 the Boyne and some lesser rivers take their rise. 

 Along the banks of the river Inny which, rising 

 in Lough Iron, in County Westmeath, crosses 

 Longford, and falls into the Shannon are large 

 tracts of deep, wet bog, only exceeded in dreari- 

 ness by that which for miles skirts the Shannon 

 in its course through Longford, Roscommon, and 

 King's County. These bogs consist of turf or peat 

 in various degrees of condensation from a pulpy 

 or fibrous mass, to a compact mass that admits of 

 being cut into any form. They rest on a sub- 

 stratum of clay and limestone gravel, are from 15 

 to 40 feet in depth, and are composed chiefly of 

 aquatic vegetables, which have grown on the sites 

 where they are now entombed. Notwithstanding 

 the quantity of water contained in these extensive 

 bogs, there arises from them no miasma injurious 

 69 



to health. This is attributable to the large portion 

 of tannin they contain, which possesses so strong 

 an antiseptic quality, that bodies plunged into a 

 deep bog remain undecayed, the flesh becoming 

 like that of an Egyptian mummy. It sometimes 

 happens that a bog, overcharged with water during 

 a rainy season, breaks through the obstruction 

 which the drained and more solid part affords, 

 and, rushing forward, overflows large portions of 

 good land. 



'The central plain,' continues Dr Clyde, 'is 

 drained chiefly by the Shannon, which is the 

 largest river in the British Islands, and the only 

 considerable one on the western shore of Ireland ; 

 it is navigable to Lough Allen, a distance of 240 

 miles. Other rivers draining the central plain 

 are the Erne, which, like the Shannon, traverses 

 several lakes in its course ; the Liffey, navigable 

 only to Dublin ; and the Boyne, navigable to 

 Navan, a distance of 25 miles. Most of the rivers 

 belonging to the mountainous regions are small ; 

 the more considerable are in the south of Ireland, 

 the Slaney. the Barrow, the Blackwater, and the 

 Lee, forming respectively the harbours of Wexford, 

 Waterford, Youghal, and Cork. The river Bann is 

 the outlet of Lough Neagh, the largest lake in the 

 British Islands ; its waters petrify, but its scenery 

 is uninteresting, as the shores are low and flat. 

 On the other hand, the three lakes of Killarney, 

 at the base of Macgillicuddy Reeks, in Kerry, 

 compete with those of Cumberland and Scotland 

 in beauty. The Devil's Punch Bowl, in the same 

 neighbourhood, is a mountain hollow, so called 

 because mist is almost always floating above it.' 



GEOLOGY. 



A great series of grits and slates of Cambrian 

 age occur in the south-east of Ireland ; the upper 

 portion contains a few fossils of zoophytes and 

 worms. Lower Silurian strata rest unconform- 

 ably on the Cambrian rocks in the same district. 

 Detached portions of Upper Silurian measures 

 occur on the western side of the island, in Kerry, 

 Galway, and Mayo. 



Between the Silurian and Old Red Sandstone 

 is an enormous thickness (11,000 feet) of sand- 

 stone grit and shale in Kerry and Cork. These 

 strata are almost wholly unfossiliferous. 



Old Red Sandstone strata, consisting of red and 

 yellow sandstone and slate, cover a large tract of 

 the south of Ireland, stretching almost continu- 

 ously from the extreme west of Cork and Kerry 

 into Waterford and Kilkenny, being stopped by 

 the Silurian rocks of Wexford and Carlow. 



The Carboniferous Limestone is extensively 

 developed in Ireland, occupying the whole of the 

 centre of the country, except in those places 

 already alluded to, where the older rocks appear 

 on the surface. This great tract is an extensive 

 plain covered with drift, and with peat-moss and 



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