The Silicificd Wood of Loui^^h Ncaj^/i. 105 



necessar}' to endeavour to define tlic ix^sition or Kccjlo^ical a^^e 

 of the beds to which they belong. 



The officers of the Geological Survey' have assigned them to 

 Pliocene age, evidently from stratigraphical evidence only. 

 In 1883 and 1884 Mr. J. Starkie Gardner, K.^.S., F.G.S. paid 

 several extended visits to Belfast in furtlierance of his researches 

 in Tertiary floras. The writer had the advantage of accom- 

 pan5dng him to the best fossil localities. On the visits to 

 I.ough Neagh large collections of the silicified wood and the 

 ironstone nodules associated with it were made ; many of 

 these nodules were exceedingly rich in plant remains, 

 in beautiful preservation, and they afford a key not previously 

 examined, to the age of the beds. The plant-bearing beds in- 

 terstratified with the basalts also received close attention, 

 Ballintoy, Ball3'palady, and Glenarm j'ielding a vast store of 

 fossil evidence. To be brief, the results of Mr. Gardner's ex- 

 aminations of these, in the light of experience gained by 

 working in all the English Tertiary deposits, as well as many 

 on the continent, in Scotland, Iceland, and Madeira, will 

 perhaps be best summed up by an extract from a paper which 

 he read : — 



"The plants which these nodules contain are most diversified, thouc(h 

 usually small-leafed dicotyledons, which at first sight seem of very 

 modern aspect. On closer examination, however, many are found to be 

 characteristic of English Middle Eocene, and others of Lower Eocene. 

 Others are common to Ballypalady, to Mull, and to Greenland. This 

 mixture of types so separated elsewhere would be difficult of explanation 

 did the thickness of the deposit not warrant the belief that it may have 

 been continuoUvSly forming throughout more than one period of the 

 Eocene. Most of the plant-remains come probably from the higher 

 horizons now exposed on the shores of the lough ; but some of them 

 from the Boulder clay may come from much lower zones in it. The 

 flora, however, is by far the most important link yet discovered between 

 the Eocenes of England and those of high northern latitudes, and as 

 such is deserving of most attentive study.'-^ 



To summarise, the Lough Neagh silicified wood (as dis- 

 tinguished from the few examples found in the basalt, which 

 bear but little outward resemblance to it) is found in the lig- 



1 Memoirs of the Geological Survey ; Explanatory Memoir to sheet 35, 

 page 72. 



2 The Lower Eocene plant beds of the basaltic formation of Ulster, by 

 J. Starkie Gardner, Esq., F.L.S., F.G.S.— O.J.G.S., February, 1SS5. 



