3^2 [Proc. B. N. F. C, 



elusion that we cannot escape the deduction that the beds of 

 Ballypallady, Isle of Mull, those near Shane's Castle, and at 

 Laurencetown, together with the Silicified Wood, and their 

 associated lignites of Lough Neagh, are of the same age, namely 

 miocene, as supposed by various writers. 



Taking the literature of the subject in its order, the 

 next reference we have to these Lough Neagh beds is 

 that made by the officers of the Geological Survey, and as 

 their opinions are of great weight, it is necessary to examine 

 them carefully. Sheet 47, and its explanatory memoir, de- 

 scribing the neighbourhood of Armagh, was issued in 1873. 

 Sheet 35 and its explanation descriptive of the Tyrone Coal- 

 fields, and the South- West corner of Lough Neagh, appeared 

 in 1877 ) these clay beds are there described fully, under the 

 head of Pliocene Clays, their thickness being estimated at over 

 500 feet. The results of many borings and sections obtained in 

 pits are given. Nearly all of these have records of Lignites 

 and Ironstone nodules, the latter in one place containing reed- 

 like plants. The writers are careful, however, to note that " in 

 no instance has any specimens of the Silicified Wood of Lough 

 Neagh been found in them, although a good opportunity for its 

 discovery has thus been afforded over an extensive area." 



The memoirs and sheet 27 appeared in 1881, and there is 

 again another chapter on the Pliocene clays continued into the 

 area which they represent. The author says — ''That the fossil 

 wood is more or less directly connected with the lignite seems 

 to be generally admitted, but there has existed diversity of opi- 

 nion as to the nature of this relation ;" and he then proceeds 

 to give one of Dr. Barton's definite statements, and quotes the 

 paragraph describing his digging into the lignite deposit where 

 some of his largest specimens were found, and concludes with 

 the following paragraph : — " Mr. Hardman, one of the sur- 

 veyors, supposes that the silicified pieces of wood had their 

 locus in the basalt, and that the silicification is due to the per- 

 colation of water through the porous and easily decomposable 

 rock. That this process does take place, at least to some 

 extent, appears from a note to Dr. Macloskie's paper, referring 



