304 Peat Bogs. (July, 
grow at the same altitudes as those at which the corkers are 
found in the bogs, but then it must be remembered that 
these places are probably at least 50 feet lower than they 
were when the oaks flourished ; besides, the bog oak occurs 
in exposed situations in the west of the island, where now 
no trees of the same dimensions would grow; and deal at 
the present day cannot be grown at the altitudes or in the 
situations where large bog deal sticks are found. 
The history of the submarine and estuary peats may be as 
follows:—When the land was about 4o or 50 feet higher 
than at present, or even more, forests grew; subsequently 
the drainage became defe¢tive, either from the land sinking 
or from the growth of ferns, mosses, and the like,—probably 
the latter,—till eventually the forests disappeared, and bogs 
replaced them. Afterwards the land must have been de- 
pressed, and probably in general rapidly, for if the sinking 
was gradual the upper strata of the bogs would have been 
formed from the growth and decay of flaggers, reeds, and 
other marsh plants, while usually the peat seems to have 
formed from the same class of vegetation as that which is 
now forming the upland bogs. 
In the subaérial bogs the decay of the oak forest would be 
somewhat similar to the decay of the woods at the com- 
mencement of the submarine peats, as the growth and decay 
of ferns, mosses, and other denizens of a forest, would gra- 
dually stop the drainage, and produce bogs in all low-lying 
places; these eventually would extend their limits, until all 
the woods on the low lands were destroyed and covered by 
peat; but the stoppage of the growth of the bogs and the 
advent of the deal forest is more difficult to explain. 
Deal trees could not be introduced or flourish on a bog 
until it was first drained and dried, and how this was accom- 
plished can only be conjectured. It seems impossible that 
the drainage of the bogs could be due to artificial means, for 
although we know portions were reclaimed at different times, 
yet such reclamation could not have been universal, and in 
all parts of Ireland the pine forests seem to have existed at 
the same time; we are therefore forced to believe that they 
were introduced by natural causes. At the present day we 
have about five wet years, five of average character, five fine 
years, five of average character, and so on, in recurrent 
cycles; but a similar climate would not have furnished fa- 
vourable conditions for the growth of the pine forests. We 
must therefore suppose that there was a long period of 
drought inauspicious to the growth of peat-producing plants, 
during which the bogs became drained, dried, and consoli- 
