Reviews . 



The Geology of South Australia. By Walter Howchin. Pp. xvi 

 + 543. Figs. 330 and geological map. Adelaide: Govern- 

 ment Printer, 1918. 



Hitherto there has been no book which treated geologic processes 

 and the general principles of geology from the Australian standpoint, 

 although The Geology of New South Wales by Siissmilch may be cited as 

 an admirable text on the historical geology of that interesting state. 

 A feeling that there was need for a work on general geology with illus- 

 trations drawn from Australia has led to the present volume. 



This volume is in two divisions. The first portion, which makes up 

 more than half of the book, deals with geologic processes, the materials 

 of the earth, and dynamic principles; the second portion outlines the 

 historical geology of South Australia. While limited space precludes 

 an exhaustive treatment of geologic principles, the reader nevertheless 

 finds a great deal of well-illustrated material within these pages. The 

 examples, illustrations, and concrete facts, taken largely from the 

 Australian continent, come with a special freshness to the geologist of 

 the Northern Hemisphere, to whom they are largely new and decidedly 

 welcome. 



A few points of dissent may be noted. The author's classification 

 of the different forms of glacial deposits is perhaps not altogether 

 orthodox from the viewpoint of others, as may be illustrated by the 

 following statement, which appears under the heading of " Unstratified 

 Glacial Deposits," on pages 146-47: "Subglacial streams wear irregular 

 channels through the ground moraines, and when the ice disappears 

 irregular ridges or mounds of drift are scattered over the valley bottom 

 and are known as eskers, in Iceland; kames, in Scotland; osars, in 

 Sweden; and drumlins, in America." On page 215, below a diagram 

 illustrating slaty cleavage in a much-folded section, the statement is 

 made that "cleavage planes preserve an exact parallelism and identical 

 strike over wide areas, and are independent of the foldings of the rock 

 as well as the bedding planes." Instead of being independent of the 

 folding, flow cleavage has recently been shown to be developed parallel 



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