596 - REPORT— 1902. 



I must pass over the subjects of paramorphism and pseudo-morpliism, as the 

 limited time at my disposal does uot permit me to enter upon tliese subjects. 



In the above sketch I have contented myself with a brief discussion of some of 

 the leading principles that seem to me to underlie contact action and meta- 

 morphism in the wet way, because I venture to thinli that, if we really understand 

 these two divisions of our inquiry, it will be unnecessary on the present occasion 

 to enlarge on other branches of our subject. 



Take, for instance, what is commonly called dynamic metamorphism. The 

 main factors in this kind of metamorphism are the folding, crumpling, crushing, 

 and shearing of rocks by earth movements, especially during the upheaval of 

 mountains. 



But these dynamic forces are potent factors in the development of heat. 



In the case, therefore, of dynamic metamorphism, as in contact metamorphism, 

 pressure and heat are the main factors acting in conjunction with the water shut 

 up in or circulating through a rock. If we understand how these factors operate 

 and produce the results we see in cases of contact metamorphism, we shall not 

 fail to understand their action in a case of dynamic metamorphism. 



These observations also apply to regional metamorphism ; that is to say, to 

 metamorphism produced in rocks at great depth, by being brought within the 

 infl-ueuce of the interior heat of the earth. The action of heat in increasing 

 molecular motion and kinetic energy is well understood nowadays, and so long 

 as we get heat it seems to me immaterial how heat is generated in rocks subject to 

 metamorphic action. 



In the above sketch I have intentionally omitted to enter into the details of 

 chemical and mineralogical action that lias brought about individual cases of 

 metamorphic change. 



Volumes would be required to do justice to so complex a subject, and the 

 details would, in an opening Address, be out of place. 



In conclusion I have, I trust, shown how important a part water plays as an 

 agent of metamorphism, not only at and near the surface of the earth, but at 

 plutonic depths. We have seen that the molten granite of the Satlej Valley, 

 which was given as an illustration of a fluid igneous magma, contained a con- 

 siderable proportion of water held in solution at considerably above red heat, and 

 that the fluidity of the magma was due to its presence. We also saw that the 

 great heat to which the magma was raised increased the potential energy of the 

 contained water when a relief of pressure opened the way for the intrusion of 

 the molten magma into neighbouring rocks. We also saw that this water was 

 rendered by heat a powerful solvent, and that it carried with it into the adjoining 

 rocks the mineral matter of the granite in solution. AVe also saw that heat 

 increased the porosity of minerals, facilitated the passage of liquids laden with 

 mineral matter through their pores, and increased the potency of chemical action. 



The following Papers and Reports were read : — 



1. Tlte Geology of the Country in the Neighbourhood of Belfast. 

 By Professor Grenville A. J. Cole, F.G.S. 



Belfast stands between the lava-plateaux of Cainozoic age in Antrim and the 

 undulating surface of Silurian rocks in Co. Down. The special interest of the 

 district lies in the preservation of Mesozoic rocks, which elsewhere are scarcely 

 represented in Ireland. Schists and gneisses in the north-east of Co. Antrim 

 possibly represent Archtean masses refolded during the Caledonian earth-move- 

 ments. The Caledonian folds gave us the crumpled county of Down, and admitted 

 the granite of Newry and Castlewellan along an axis running north-east and 

 south-west. Both Ordovician and ' Upper Silurian ' (or Gotlandian) strata are 

 represented in this area. The conglomerate of Cushendun is probably of Old Red 

 Sandstone age ; but the Carboniferous Limestone, which is so marked a feature of 

 Ireland as a whole, plays only a small part in the north-eastern counties. The 



