Clare Island Survey — Tree-Groivth. 9 15 



Observations over a certain number of years may give results at a given 

 point, but they afford no evidence of the rate of growth of a bog, which may 

 have been mountain or heath peat at one period or at one spot, marsh peat 

 at another, and Sphagnum peat at a third ; nor do they enable one to judge 

 of the periods of time during which a bog may have increased in thickness, 

 remained stationary, or decayed from time to time, according to the prevailing 

 local or climatic conditions. The depth of peat underlying or overlying a 

 root bed, therefore, does not necessarily prove the age of the latter, nor does it 

 necessarily follow that the deepest bogs are the oldest. Probably the surface 

 area of a bog would be the best standard of age, as it implies the result of 

 climatic and other conditions upon different soils and situations, but, even 

 here, many factors of acceleration and retardation of an uncertain nature 

 have to be taken into account, and the most careful estimate may be wide 

 of the mark. 



The only facts which appear to throw some light upon the antiquity of the 

 Pine, and the approximate date of the Oak and Pine period, are the traces 

 of submerged forests round the coast of Ireland and Great Britain, the 

 names associated with the ancient townlands into which Ireland is divided 

 and the materials of which the crannogs are built. The first shows that 

 Oak and Pine, together with Hazel and other species, existed in the country 

 when the land stood well above its present level, and that if a pure Pine and 

 Birch period existed, it must have been, if anything, earlier than the final 

 submergence of the land. The names of townlands suggest that while Oak 

 must have been common at the time they acquired the reputation upon which 

 their nomenclature was based, the existence of the Pine at that period, 

 probably somewhere early in the Christian era, is very doubtful. The 

 remains of the various crannogs, which go back to Pagan times in Ireland, 

 prove the abundance of Oak and Hazel in their construction, whde Pine is 

 conspicuous, not by its absence, but by its rarity, and appears to be confined 

 to the more ancient structures. 



As regards the submerged forests, Pine, Oak, Birch, Hazel, &c., appear 

 fairly generally distributed amongst them; but in one at least, Ardmore. 

 county "Waterford, no trace of Pine could be found by the writer. In 

 Blacksod Bay, and at Bray, county Wieklow, the distribution appears to be 

 Pine at the deeper level, and Oak within five to ten feet of high-water mark, 

 following the order found in the peat bogs round the English coasts. 

 Clement Eeid 1 records Oak, Hazel, &c, but Pine in one or two instances only, 

 and he attributes the submergence to the Xeolithic Period. Praeger also 



1 " Origin of British Flora." : Proc. E. I. A., series ii, vol. iv. 



