Reviews — Xinahan's Valleys, etc. 131 



and water; and to picture the forms of animal and vegetable life that 

 have from time to time existed. But there is another, and perhaps to 

 the majority of mankind, a higher aim in Geology, one that also leads 

 to noble thoughts and lofty aspirations — sometimes also to the realiza- 

 tion of large fortunes — the study of Economic Geology. 



The application of Greology to the Arts and Manufactures has been 

 brought prominently before us by Professor Ansted in several published 

 "works. They have been illustrated in the Museum of Practical Greo- 

 logy, and special branches of the subject have been treated of in works 

 by Prestwich, Hull, Smyth, and many others, as well as in the Reports 

 of some of our Royal Commissions. The connexion between Greology 

 and other sciences is as much displayed in its economic bearings as 

 in its purely natural history relations. 



Dr. Page has produced a very comprehensive work. The relations 

 between Geology, Agriculture, and Land Yaluation are discussed, 

 likewise those in connexion with Architecture, Civil and Mine 

 Engineering. One chapter is devoted to Heat and Light producing 

 materials ; and another to Geology and the Eictile Arts, treating of 

 the Clays we fabricate, the Sands we vitrify, and Glazes, Enamels, and 

 Colours. Chapters are devoted to Grinding, Whetting, and Polishing 

 Materials ; to Refractory or Eire-resisting substances ; to Pigments, 

 Dyes, and Detergents ; to Salts and Saline Earths ; to Mineral and 

 Thermal Springs ; to Mineral Medicines ; to Gems and Precious 

 Stones ; and, lastly, to the Metals and Metallic Ores. 



At the end of each chapter Dr. Page has enumerated some of the 

 most important works that may be consulted when details on particular 

 subjects are required. In a work of so comprehensive a kind as this, 

 it is impossible not to find some subjects which appear to be rather 

 scantily treated. We might have expected some particular notice of 

 Irish peat, or a reference to the localities in England where it has been 

 dug. The ages and modes of occurrence of the clays we fabricate are 

 hardly noticed at all. But we must not forget the cosmopolitan 

 nature of the work, and that the addition of much more material would 

 have rendered it too bulky for a Text-book. We may congratulate 

 Dr. Page in having produced this book, which cannot fail to be very 

 largely and widely appreciated. 



II. — Valleys and their Relation to Fissures, Fractures, and 

 Faults. By Gr. H. Kinahan. 8vo. pp. 240. (London : 

 Trubner & Co., 1875.) 



THOSE who have been spectators of the course of Geological Theory 

 during the past ten or fifteen years must have been struck by 

 the many, seemingly one-sided, explanations that have been given to 

 account for the origin of the present land configuration. The early 

 teachings of Hutton, and of Scrope, have perhaps been more fully 

 appreciated in late years than they were fifty years ago. 



The effects of rain and river action have been more fully explained, 

 and the great influence of glacial action in comparatively recent times 

 has been also taken into account. Nor has the agency of the sea been 

 neglected, although it has been clearly proved that meteoric agencies 

 combined, by reason of the greater surface they have to act upon, far 



