Reports and Proceedings — Geological Society of London. ;i33 



The volume is illustrated by 44 plates and 3 maps, in addition 

 to a large number of woodcuts. There are pictures of damaged 

 and utterly ruined houses, monuments overthrown and twisted on 

 their bases, railway lines crumpled as if they were made of wire, 

 and fissures, sand-vents, and fault-scarps, as well as the diagi'ams of 

 distant magnetographs and horizontal pendulums. Many of these 

 are worthy of a wider circulation, and will doubtless live again in 

 books made better by their presence. C. Davison. 



I^EI='OI^TS j^isriD I'I^OGs:BXDI3:^^a-s- 



Geological Society of London. 



L— May 23. 1900.— J. J. H. Teall, Esq., M.A., F.K.S., President, 

 in the Chair. The following communications were read : — 



1. " The Igneous Rocks of the Coast of Count}' Waterford." By 

 F. R. Cowper Fteed, Esq., M.A., F.G.S. 



The first part of this paper is devoted to a discussion of the field- 

 evidence, as shown by the coast-sections from Newtown Head to 

 Stradbally. The igneous rocks there exposed are divided into the 

 following six categories: — (a) The felsitic rocks ; [h] necks of non- 

 volcanic materials ; (c) the basic sills and vents ; {d) intrusions of 

 dolerite ; (e) intrusions of trachyte, andesite, etc. ; (/) intrusions of 

 other types. In regard to the age of the rocks, there appear to 

 have been two main periods of volcanic activity : the first, in 

 Ordovician times, was marked solely by outpourings of a felsitic 

 nature; the second, post - Ordovician but pre-Upper Old Red 

 Sandstone, was characterized by a succession of several distinct 

 types of igneous rocks. The lavas and tuff's, interbedded with 

 fossiliferous rocks, have been already described. These are overlain 

 by other felsites and ashes, developed near Great Newtown Head, 

 which show the same dip and strike and partake in the same move- 

 ments. Next occurred an outburst of green and pink felsites, tuff's, 

 and coarse agglomerates, developed from Great Newtown Head to 

 Garrarus ; and possibly the xenolithic felsites and greenish tuffs 

 belong to the same series. It is doubtful whether these were 

 poured out before the first folding of the Ordovician beds, but their 

 strike, when traced inland, agrees with that of the series last 

 mentioned. The intrusion of some irregular masses of felsite- 

 porphyry took place subsequently to the folding ; it was followed 

 by small veins of trachyte and andesite ; these by basic sills, 

 diabases, etc., and by a few dolerite-dykes and veins. Subsequently 

 the igneous intrusions assumed an acid character, and the felsitic 

 masses of Newtown Head, Knockmahon, etc., were extruded ; 

 probably at this time, too, were formed the isolated necks filled with 

 brecciated fragments of the earlier rocks. The felspar-porphyry 

 dykes and isolated felsitic sheets and veins which pierce the folded 

 rocks, particularly west of Kilfarrasy, probably belong to this late 

 period. 



