The Geology of South Australia

FOLLOWING the example of Mr. Chapman's Australian fossils—an outline of palaeonto logy based on Australian examples for Australian students—Mr. Howchin, of the University of Adelaide, has prepared a general text-book of geology based on Australian illustrations, followed by an account of the geology of South Australia, with shorter summaries of that of the other Australian States. The book should be very useful, as it fills a gap in Australian educational literature, while it supplies geologists in general with,an excellent and up-to-date compendium of the geo logy of South Australia. Mr. Howchin is exceptionally qualified for the work; he is well known for his discovery of the Australian Cambrian glacial deposits, his researches on fossil foraminifera, and his text-book, on the geography of South Australia. The first division of the work gives a clear summary of the general outlines of geology; it is especially good in the physiographic portions. The petrology. As comparatively ele mentary, since the book, being published by the South Australian Education Department, is probably intended more for secondary schools than for university students. Aus tralian petrologists may consider that there is inadequate notice of the alkaline igneous rocks and in an effort at simplification “pyroxene (augite)” is included in the hornblende group, a step which would lead students to overlook the important distinction between the pyroxenes and othe amphiboles. The parallelism of these series is also not indicated in the statement as to the com position of augite. There is not much informa tion about economic geology; for example, the author tells us nothing about the oil-fields of South Australia and their prospects. He follows those who extend the petrographiq use of the word “mineral” for mineral species into general geology, although mineralogists, such as Miers, adopt the more commonsense practice which does not refuse the term “mineral” to most economic minerals. The author, of course, cannot be consistent, for the term is not used in the latter part of the book in accordance with the restricted definition. In regard to the Australian artesian water, the author adduces evidence that the supply is dwindling from the reduction in size,of the mound springs; but those who hold that plutonic water is largely influential in the uplift,of the water in the wells do not consider, as is twice stated, that most of the water is plutonic in origin. The Geology of South Australia.