Reviews — T. Mellard Reade — Earth Structure. 79 



like a stratified series into which veins of igneous rock had been 

 • injected — an inference much to the credit of his powers of observance, 

 the move so since the feature seems to have escaped the notice of. 

 subsequent investigators. The rocks of this series show great 

 variety in hand specimens, but two types predominate, one of which 

 is of considerable mineralogical interest. Under the microscope 

 this green-bedded rock is found to contain, in addition to garnet and 

 ■epidote, a considerable quantity of scapolite and white augite, which 

 latter is plentiful together with numerous crystals of sphene. 

 " The abundance of scapolite in an undoubtedly altered calcareous 

 shale is perhaps the most noteworthy feature of this rock." Thus 

 we find that if this metamorphic series has so far contributed nothing 

 organic which might throw any light on its age or origin, yet as 

 a contact rock it produces a greater variety of minerals than the 

 more massive gneisses which surround it. 



The general conclusion to which Professor Garwood arrives is, 

 that the bulk of the gneiss, and particularly the augen-gneiss, must 

 he regarded as an igneous rock, and he is disposed to attribute the 

 metamorphism of the sedimentary series directly to its intrusion. 

 Tlie evidence is in favour of the sedimentary series, in two cases 

 at least, being of Palaeozoic age, and he suggests that the gneiss was 

 'intruded as a huge laccolitic mass during the folding which accom- 

 panied the elevation of the range. Such a fan -like fold would help 

 to account for the inverted dip of the beds towards the roots of the 

 •chain, a feature which seems to be in accordance with the inward 

 dip of the foot-hills in parts of the north-west Himalayas. 



W. H. H. 



II. — The Evolution of Earth Structure, with a theory of 

 GEOMORPHic CHANGES. By T. Mellard Eeade, F.G.S., etc. 

 pp. XV, 342, with forty plates. (London : Longmans, Green, &Co., 

 1903. Price 21s. net.) 



rSlHE volume before us may be taken as the sum and substance 

 L of the author's observations and conclusions with respect to 

 the structure of the earth, the changes which the rocks have 

 undergone, and the origin of the movements which have effected 

 the earth's crust. While he claims that " Nearly the whole of 

 the matter is original, and the greater part quite novel," it is 

 ■understood that this applies to work that has extended over some- 

 thing like forty years, and that much has previously been printed 

 in Journals and Proceedings of Scientific Societies, in his essay 

 on "Chemical Denudation in relation to Geological Time" (1879), 

 and in his volume on " The Origin of Mountain Ranges considered 

 experimentally, structurally, dynamically, and in relation to their 

 Geological History " (1886). This last work was reviewed by 

 the Rev. Osmond Fisher in the Geological Magazine for 1887 

 (pp. 229-233). 



The present work is divided into three ' books,' of which the first 

 deals with georaorphic changes. The subject is illustrated by 

 a useful diagram, drawn to scale, showing half the sphere ; with 



