1874.] Peat Bogs. 297 
The normal lowland or ‘‘red bogs” of the central plain 
of Ireland are very similarly circumstanced to the ordinary 
coal seams, having an under-clay which is more or less pene- 
trated by the roots of the trees and larger plants which at 
the first occupied the land. In most of them, as also in 
many other low-lying bogs, the roots and the trunks of the 
trees under the peat, or in the lowest strata, are principally 
those of oak and yew, as if prior to the growth of the peat 
the low country was for the most part a vast forest of these 
kinds of trees, the oak greatly preponderating. In these 
forests mosses and other peat-producing plants began to 
grow and flourish, till eventually they stopped the drainage, 
and formed an envelope of peat which gradually killed the 
trees, while subsequently the stems rotted off, between wind 
and water, the trunks toppling over and being entombed by 
the succeeding growth of the peat. After the disappearance 
of the major portion of the oak forest, the bogs for years 
gradually increased in depth, till suddenly—from some as 
yet unexplained cause—their growth ceased, and on their 
surfaces forests of deal sprang up. During all this time, 
however, portions of the original oak forest were preserved, 
and some of them apparently remain in certain places to 
the present day. This seems to have been due to the oaks 
and associated trees being destroyed only in those compara- 
tively level places in which the peat could easily accumulate. 
On hills that were above the general level of the peat the 
oak would still flourish, and during the ‘‘ Deal Forest Age” 
each of these hillocks remained an oak grove. At the pre- 
sent day, in many parts of Ireland, the hills and exposures 
of drift in a flat bog are called “‘derries” (Anglice, oak-woods), 
the ancient name, which has survived down to the present 
age from the time when they were oak groves surrounded by 
forests of deal. Still this name may be more modern, as it 
is probable that, even after the deal forests disappeared, 
many of these hills still remained oak-woods. ‘The derries 
in the midland counties of Ireland have long since been 
cleared of their timber, and are now under tillage or grass 
land, but in a few places—such as some of the wild tracts 
in Mayo—the oak may still be found growing on the drift 
islands in the bogs, it always being associated with yew, 
hazel, birch, ash, and holly; probably the last three trees 
were also denizens of the primary forests, but their timber 
has long since disappeared, they being of kinds that rot 
quickly in bog. 
That such was the mode of the growth of the bogs is 
proved by the different sections exposed, as beneath the peat 
