Dr. Berger’s Account of the Isle of Man . 
499 
DILUVIAL DEPOSITES. 
Curragh is a name given, in the Isle of Man, to any tract of peat 
bog. A large extent of land, called the Curragh , now under 
cultivation, and lying to the north of the mountainous tract, 
formerly consisted of this substance. 
Much discussion has been excited in the island concerning the 
origin of its peat, some affirming that it is daily formed by the 
decay of certain aquatic plants, whilst others attribute its existence 
to the ruin of ancient forests. Those who favour the former 
hypothesis draw their conclusion partly from the phenomena 
observed upon cutting it. The method pursued is to take off the 
surface, which consists of vegetating matter, and having dug a 
trench to the depth of a few feet, to replace this on this bottom, 
when, in the course of time, this trench becomes filled up by a fresh 
body of peat, a circumstance attributed to the growth of the 
vegetable that is found on the surface. The opposite hypothesis 
accounts for the trench becoming replenished, by supposing the 
peat which forms its walls and base to yield to the pressure existing 
on all sides, and thus gradually filling up, in the manner that a ditch 
becomes obliterated when dug in soft mud. 
It is not my intention to enter into an examination of the merits 
of either hypothesis, nor have my sparing observations on this head 
at all qualified me for such an office. Perhaps to the union of the 
two causes may be attributed the formation of the curraghs in the 
Isle of Man ; but certain it is that some great catastrophe has here 
overwhelmed large tracts of forest land, and I am indebted to 
H. R. Oswald, Esq. of Douglass, for much of the information 
I received respecting the nature of these and the various trees, 
which are found buried in them. 
