228 Proceedings of the Royal Irish Academy. 



we to believe that such upwellings, implying local relief from pressure, 

 are unaccompanied by incorporation and assimilation on a considerable 

 scale? Even Salomon himself, who shows that the variations in the con- 

 stitution of the enormous mass of tonalite are not related to the nature of 

 the contact rocks, presents us with a section^ illustrating " lit par lit " 

 injection above the Poglia valley, where the igneous rock assumes a 

 bedded structure, and includes residual and parallel strips of altered 

 Triassic limestone. The resemblance of such structures to those near 

 Finntown is apparently complete ; and the author attributes the 

 position of the tonalite between the sedimentary bands to the solution 

 of certain shaly layers, as the tonalite sent off apophyses into them. 

 Salomon still concludes, as in an earlier paper, ^ that the gneissic 

 structure of the tonalite is due to subsequent dynamic action, despite 

 the occurrence of a little true fluidal structure here and there f but 

 his work is nowhere opposed to the views above stated in explanation 

 of the gneiss of Boylagh. 



More than twenty years ago, Mr. G. W Hawes* called attention to 

 the production of mixed rocks on an important scale at the contact of 

 granite in ITew Hampshire ; and there is little difference between 

 his statements and those made so clearly by Lacroix^ in 1898 con- 

 cerning the composite gneisses of the valley of Baxouillade. Con- 

 siderable stimulus will now be given to such enquiries by the remarks 

 of Mr. TealP in his Presidential Address to the Geological Society of 

 London in 1902 ; and it is probable that the importance of composite 

 gneisses will be recognised in many areas, where the prevalent 

 structures have hitherto received other interpretations. 



^ " TJeter Alter, Lagerungsform, und Entstehungsart der periadriatischen 

 granitisch-komigen Massen," Tscherm. Mittheil., Bd. xvii. (1898), p. 159. 



- "Neue BeobacMungen aus den Gebieten der Cima d'Asta und des Monte 

 AdameUo," Tscherm. Mittheil., Bd. xii. (1891), p. 411. 



' Op. cit., Tscherm. Mittheil., Bd. xvii., p. 131. 



* "The Albany Granite and its Contact Phenomena," Amer. Jour. Sci., vol. 

 Kxi. (1881), pp. 31 and 32. 



5 Op. cit. (1898), p. 49. 



^ Proc. Geol. Soc, pp. Ixxiv and Ixxviii, in Quart. Journ. Geol See. for 1902. 



