6 44 [Proc. B.N.F.O., 



As to the possible glacial origin of the hollow, reasons will 

 presently be given for the belief that the deposits were in all 

 probability preserved during the periods of glacial-erosion rather 

 than that the hollow should be attributed to such a cause. The 

 clays moreover in certain places underlie Boulder-Clays ; and 

 portions of the lignite, of the lake region, have been detached and 

 carried northward by the ice. 



The conclusions to which this array of facts, and somewhat 

 anomalous hypotheses, point, seem to me fairly obvious ; they are 

 given in the following summary, and it will be noticed that they 

 form an amplification of the possibility mentioned by Sir A. Geikie,* 

 viz. : that " the pipe-clays and lignites " of Lough Neagh " may 

 belong to the sedimentary zone that separates the Lower and 

 Upper Basalts." 



t. — It is not unlikely that the Upper Basalt is of greater 

 extension on the east side of the lake than has hitherto been 

 supposed ; and it may ultimately be proved to encompass the lake. 



2. — The lignites with the accompanying silicified wood and 

 clay iron-ore, near the lake-shore, represent generally the Inter- 

 basaltic Zone of Antrim. 



3. — The Zone is also probably represented by the lignite 

 south of Clare, near Banbridge, which would relegate the covering 

 rock to the Upper series of sheets. 



4. — The Lower Basalt may not occur much to the southward 

 of the middle of Lough Neagh, along a line north-westward by 

 Ballinderry and Coagh, and northward of Craignashoke ; thence 

 eastward by Lyle's Hill ; while the Upper Basalt occurs as far at 

 least as the opening just referred to, south of Clare. 



5. — The Lough Neagh Clays, though a continuous series, 

 consist of deposits belonging to five different stages, as follows, 

 beginning with the oldest :— 



* "Ancient Volcanoes," Vol. II., p. 450. 





