Palaeogeography, Palaeoclimatology, Palaeoecology Elsevier Publishing Company, Amsterdam - Printed in The Netherlands

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Geology of the Alaska Peninsula-Island Arc and Continental Margin. C. A. BURK. Geological Society of America, Memoir, 99 (pt.l-3), 250 pp., U.S. 28 illus., 8 plates, 1 table, $20.

The memoir consists of a text (156 pp. q- 86 pp. appendices) plus geological and tectonic maps. The text is split up into chapters on the Paleozoic, Mesozoic and Cenozoic rocks, the Mesozoic and Cenozoic history of the peninsula, the principal structural features, regional structural geology and a concluding chapter on the peninsula as an island arc and continental margin. Each chapter is sub- divided, each subdivision with its summary. The appendices contain the details necessary to the memoir but which would obtrude in the text. The eight pages of references help to make the memoir an exceedingly useful source book for anyone interested in learning something of the history of an interesting region.

The interest of the region resides in the fact, as the author indicates in the first sentence, that: " . . . it represents the continental margin of southern Alaska as well as part of the Aleutian island arc." In the light of the trend towards de- tailed study of the oceanic basins and current geophysical hypotheses the need for detailed studies of such regions is clearly apparent. Whilst Professor Burk was obviously aware of such considerations, he has not allowed them to colour his account but instead permitted the intrinsic interest of the geology to speak for itself.

Apart from dubious Paleozoic rocks, the history of the Peninsula appears to date from Late Norian times and, from the descriptions given, the history of the Peninsula comes strikingly to light. Burk shows that the earliest indication of the ancestral peninsula is found in the position of the Jurassic batholiths and that the present form of the Peninsula is largely a Pliocene effect. The enormous thicknesses of Jurassic and Cretaceous sediments seem to match the thicknesses recorded in Asia. Surprisingly perhaps, it appears that the Tertiary vulcanicity which continues to the present was the first important volcanic period since the Early Jurassic.

When one considers the inaccessibility of the region and the inhospitable climate, one must marvel and give thanks to Professor Burk for his achievement and to the oil company who supported him. The text, though somewhat dis- jointed by the frequent summaries, is well written, the book well produced and up to the high standards set by the Geological Society of America. It is a book to be recommended to the attention of all geologists.

A. E. M. NAIRN (Cleveland, Ohio)

Palaeogeography, Palaeoclimatol., Palaeoecol., 3 (1967) 197-198