36 Reviews — Professor Park's Geology of New Zealand. 



good reason to hope that in the future such questions as the origin 

 and structure of igneous rocks will in the simpler cases at any rate 

 receive physico-chemical solutions. Much work must he done before 

 that day comes, but we have already an earnest of the results in the 

 work of Yogt and the chemists of the Carnegie Institution in 

 "Washington. It is becoming almost a necessary part of the education 

 of every geologist that he should be acquainted with the main 

 principles of physical chemistry as applied to geology. 



Dr. Elsden's experience as a teacher and his original work as 

 a petrologist have specially qualified him for this task. The book 

 condenses into a small space information gleaned from a wide variety 

 of sources. It is thoroughly up to date, and the only errors we have 

 noticed in it are a few printers' errors. It may be strongly recom- 

 mended to all students not only for the accuracy of its contents but 

 also for the fairness and judicial caution with which it handles such 

 thorny subjects as the origin of magmas by diffusion and the sequence 

 of crystallization in igneous rocks. 



J. S. F. 



III. — The Geology op New Zealand : an Introduction to tete 

 Historical, Structural, and Economic Geologv. By James Park, 

 Professor of Mining and Mining Geology in the University of 

 Otago, etc. 8vo ; pp. xx, 484, with geological map, 22 full-page 

 plates and maps, and 140 text-illustrations. London: Whitcombe 

 and Tombs, Ltd., 1910. 



WITH the ever-increasing volume of geological literature we 

 welcome a summary of what is known regarding the main 

 features in the geology of New Zealand, especially as the work is 

 written by one who has taken an active part in the geological survey 

 of the country and in the practical applications of the science. The 

 very useful bibliography given by the author extends over 56 pages, 

 and in preparing it he acknowledges his indebtedness to Dr. "Wilckens 

 of Bonn University. 



New Zealand possesses representatives of nearly all the main 

 geological systems, although the author is not quite right when he 

 says that the record is "more complete and varied" than that of 

 Australia. The Devonian system, at any rate, is not admitted by him 

 into the New Zealand table of sedimentary formations. Some of the 

 gneisses and crystalline schists of the Maniototo Series were regarded 

 by Hutton as pre- Cambrian or Archaean, but the rocks which are 

 admittedly the oldest in New Zealand are grouped by the author as 

 Cambrian, as they are closely associated with graptolite-bearing rocks 

 of Ordovician age. Again, the equivalents of the Oligocene are not 

 recognized in the New Zealand series. 



In the classification of the strata "it is generally conceded by New 

 Zealand geologists that the chief formations should be distinguished 

 by Maori names", and these are applied by the author both to the 

 systems and subdivisions, from the Cambrian to the Pliocene, the 

 European time-divisions being likewise indicated. The progressive 



