40 Reviews — Kinahan's Geology of Ireland. 



rocks, while the Bheetic beds above seem to graduate from them 

 into the Jurassic rocks, as they do in England. 



The Lower Lias is next described, and the alteration of the Port- 

 rush Lias into Hornstone is attributed to the intrusion of the granitic 

 rocks of the district, and the metamorphic influence of steam or heated 

 water. 



Accounts of the Greensand, Chalk, and Miocene strata are given, 

 including the Miocene Iron-ore measures. 



A description of the Pliocene Clays of Lough Neagh completes 

 the first section of the book. 



Section 2 is devoted to the Metamorphic and Eruptive rocks, and 

 here we are introduced to some new terms. Thus Metamorphic 

 action is described as in some cases Regional, extending over large 

 areas, and due to "the influence of intensely heated water or steam, 

 which, as it were, stewed them [the rocks], from which the action 

 may be called Metapepsis." In other cases the Metamorphism may 

 be Local, adjoining intruded masses of rock, etc., which give the 

 strata a baked appearance ; hence this change is termed Pakoptesis. 

 A third kind of Metamorphism, due to the introduction and action of 

 chemical substances from without, is called Methylosis. It may be 

 questioned whether the introduction of these words is a benefit to 

 the student, who would no doubt be satisfied with the terms Eegional 

 and Local Metamorphism. But Mr. Kinahan is not altogether un- 

 known for the introduction of peculiar terms, and in his Introduc- 

 tion speaks of the Eruptive rocks as Granitic or Catogene, that is 

 rocks formed beneath the surface of the earth at greater or less 

 depths ; and as Anogene, or rocks formed on or close to the surface 

 of the earth. 



Section 3 is devoted to the Superficial Accumulations, Glacial and 

 Aqueous Drifts, and Meteoric Drift (iEolian or wind-formed drift) ; 

 the subjects of Glaciation, Erratic Blocks, Eaised Beaches, and Sub- 

 merged Land and Forests, Peat-Bogs and Pre-historic Eemains, 

 Soils, etc. 



Section 4 contains an account of the Physical Features, Escarp- 

 ments, Cliffs, Hills, and Cooms, of the Valleys and Subterranean 

 Eivers, the Bays, Lagoons, Lakes, and Islands. 



Speaking of the Valleys, Mr. Kinahan says, "It is a popular belief 

 that Eivers and Streams have excavated the valleys in which they 

 flow. This may be the case in reference to some valleys no doubt, 

 but in Ireland in general, the rivers are due to the valleys, not the 

 valleys to the rivers ; the valleys occupying dykes of fault-rock or 

 lines of breaks or other skrinkage fissures in the strata or accumu- 

 lations in which they are situated." This statement, which forms 

 the opening paragraph to Chapter XIX., is well calculated to evoke 

 criticism. We are quite prepared to acknowledge that Faults, 

 Fissures, and Joints have had great influence in originating or modi- 

 fying the courses of rivers, but clearly the rivers in most cases have 

 carved out the valleys. Indeed, Mr. Kinahan himself speaks of the 

 Ovoca and its tributaries as occupying deep narrow valleys excavated 

 along lines of faults. 



