882 
THE GEOLOGIST. 
depth of one foot ia Ato years, and which, if compressed and solidified 
into one-fourth part of tliat balk," would, Mr. Moore reckoned, "bo 
as near an approach as can be made at the present day to the rate of 
increase of bogs." 
The black bog contains much woody matter, and is believed to have 
been formed on the site of ancient forests, great quantities of the 
prostrate trunks of Scotch fir, oak, beech, alder, and yew being found 
with their roots in situ. The roots of the oaks are generally nearest the 
margin of the bogs, resting on the clay or marl bottoms, while the 
Scotch firs occur further towards the centre, and rest on several feet of 
peat, thus showing that a considerable accumulation of that substance 
must have taken place before they vegetated on it. A few of the trees 
of those ancient forests, which once covered a large portion of Ireland, 
still exist on the property of the Earl of Arran. 
The mountain-bog is often found at the elevation of 2,000 feet, and 
in this variety, the grey moss, Racomitrium lamiginosum, supplies the 
place of the Sphagnum. On passing the residence of the Earl of 
Belmore, we saw, for the first time, beautiful timber, and a well-kept 
domain. Between Dublin and Enniskillen scarcely a tree is larger 
than the thistles in the gardens and corn-fields, and a fine oak tree is as 
great a novelty as a woman with shoes and stockings. The Windermere 
of Ireland, Lough Erne, separates at Enniskillen into the upper and lower 
lakes, the town being built upon an island connected by bridges with 
the main land. The country around is undulating, with bold escarp- 
ments of carboniferous limestone. The lower limestone forms the most 
extensive series of surface-rock in Ireland ; but in the northern counties 
of Fermanagh, Cavan, Leitrim, and Eoscommon, it is, in some districts, 
surmounted by the upper limestones of the series. The Culp series, 
which separates the limestones, appears to be exceedingly variable as 
to thickness, as on the north-west coast of Leitrim it exceeds 1,700 
feet, while in the county of Cavan it is not more than 400 feet thick, 
and in the valley of the Barrow, at Carlow, is altogether absent ; the 
upper limestone resting directly upon the black marble beds of the 
lower. Enniskillen is admirably situated for much condensed geology. 
At Lisbellaw, south of Enniskillen, the traveller may commence with 
marvellous conglomerates of the Old Bed epoch ; and proceeding by 
Florence Court and Culkeagh Mountain to Killargas or Riverstown, be- 
tween Loch Gill and Loth Ariow, he may study every formation, from 
