November 17, 1905.] 



SCIENCE. 



629 



all its synonyms, is omitted with much of the 

 complex nomenclature and special doctrines 

 of this new and aspiring science, while the 

 American authors present a grand chapter on 

 the ' Origin and Descent of Rocks,' starting 

 with a molten magma (but discrediting a 

 molten globe), and presenting the new quanti- 

 tative classification of Iddings and Washing- 

 ton. 



Fossils are next treated with great brevity 

 in an excellent chapter of twelve pages. Much 

 is omitted here that appears in Pennell, Cole 

 and Keilhack and might have been expected 

 in a manual of field geology. The book is 

 rather planned for an advanced course in 

 geology in Scotland with some field work, and 

 it is interesting to note the classes for which 

 it is intended according to the enumeration 

 in the preface, viz., mining engineers, civil 

 engineers, architects, agriculturists and public 

 health ofiicers. 



There follow chapters written with great 

 fullness and clearness upon the main geolog- 

 ical structures, stratification, concretions, fold- 

 ing, joints and faults, the structure of eruptive 

 rocks, and ore formations. The book is here 

 at its best. The illustrations are abundant, 

 well chosen and clear and the plan of printing 

 many of the important figures as separate 

 plates is used with especially good effect and 

 several of the landscapes combine the highest 

 artistic beauty with the greatest illustrative 

 value. Several companion plates are very 

 effective, for instance the field data of a com- 

 plex area are presented on one plate and the 

 completed map on an opposite plate. Again 

 the tracings of thrust planes are given on 

 a photograph of a mountainside and a section 

 of the intricate geology of the mountain is 

 given on a plate facing the first. 



The chapter on metamorphism is brief. The 

 Archaean is dismissed with a half page, and 

 the line of treatment is not greatly influenced 

 by the remarkable attempts to apply the laws 

 of physical chemistry to the problem made by 

 Van Hise, Grubenmann and Becke. 



Then follows a chapter of fifty-four pages 

 on geological surveying, which, as it is largely 

 given up to the description of structural fea- 

 tures, and, indeed, contains the only discus- 



sion of the glacial formation, offers only rather 

 brief and general directions for field work. 



The economic aspects of geological struc- 

 ture are then taken up in a very detailed and 

 interesting way, full of practical suggestions 

 for the application of the ideas developed in 

 the preceding chapters. 



The book closes with a brief chapter of 

 thirty pages covering the whole subject of 

 denudation and the evolution of all the sur- 

 face features of the earth, and there is no sug- 

 gestion of the survey or special field study of 

 these subjects. The contrast between the two 

 books comes out strongly here. The Ameri- 

 can book devotes 355 pages to the work on air 

 and water and 38 to structural geology. The 

 other gives 30 pages to erosion and 166 to 

 structure. The author shows a great and, in 

 the main, wise conservatism in the employ- 

 ment of new terms. Peneplain does not ap- 

 pear, nor any of the superabundant and largely 

 anthropomorphic terms used especially in 

 America in the description of topographic 

 forms and the cycle of their growth. At 

 the same time he gives with brevity a clear 

 description of the river cycle. The author is, 

 perhaps, not quite consistent as he uses the 

 new or rare word ' phacoids ' for ' augen,' 

 which is fully as bad as phenocryst. He 

 seems to wish here to avoid the German, but 

 in another connection uses lee-seite and stoss- 

 seite, when lee-side and stoss-side are good 

 English. In still another connection the word 

 hornfelses has an unattractive look. 



In this large book, given up almost entirely 

 to the presentation of facts, the reviewer has 

 wished to criticize only one minor statement. 

 It is said (p. 51) " Tachylite is altered to a 

 yellowish or reddish substance known as Pala- 

 gonite." Palagonite is certainly an original 

 volcanic glass which has cooled with its present 

 large content of water. A certain uncertainty 

 inherent in the subject may be noted in the 

 treatment of amphibolite and hornblende 

 schist. The two volumes thus supplement 

 each other in a valuable way, the one being a 

 full and well-considered hand-book for use in 

 the sober work of geological surveying or eco- 

 nomic investigation, in a country like Scot- 

 land, where there are no active volcanoes. 



