REVIEWS 527 



remainder, the lubricants from some of the oils showing a notably low 

 solidifying point. 



The most important fields are the Zorritos, Lobitos, Negritos, Cabo 

 Blanco, and Lagunitas. The district described produces more than 

 99 per cent of the total Peruvian output, and about .5 per cent of the 

 world's annual supply. Seventy-five per cent of the product is controlled 

 by the International Petroleum Company of Toronto (an Imperial Oil 

 Company subsidiary), and about 22 J per cent by a British company 

 (Lobitos Oilfields, Ltd.). 



The reviewer found the volume enjoyable to read because of its large 

 print and abundance of headings, as well as the good diagrams, maps, 

 and illustrations. There is not a little repetition of the subject-matter, 

 not all of which seems unavoidable, or desirable for clarity; but the 

 book is highly interesting and instructive, both for the general geology 

 of this unusual region, and the petroleum geology of the important oil 

 occurrence. 



T. B. R. 



Untersuchungen uber die Tektonik der Lessinischen Alpen und ilber 

 die Verwendung statistischer Methoden in der Tektonik, I. Teil. 

 By J. PiA. Denkschriften des Naturhistorischen Museums 

 in Wien. Band 2. Geologisch-Palaeontologische Reihe 2. 

 1923. Pp. 229, pis. 5, figs. 61, tables 86. (Price $4.80. 

 Orders to be addressed to Geologische Abteilung des Natur- 

 historischen Museums, Wien I. Burgring 7.) 

 The first chapters of this book are devoted to a detailed tectonic 

 description of the mountains situated between the rivers Etsch and 

 Brenta, from the Sugana Valley on the north to the plain of Venice on the 

 south. The folds of this region are very slight in comparison with the 

 rest of the Eastern Alps. They show more or less distinctly the character 

 of knee-bends. They are crossed by a richly developed system of faults, 

 mostly directed toward NNW. The description is illustrated by a table 

 of sections and by a tectonic sketch-map. 



The second part of the book is of more general importance. It deals 

 with an attempt to adapt statistical methods to tectonic descriptions, 

 which may enable us to describe in a more accurate way the direction 

 and intensity of folding in different areas. The leading idea of the 

 method described by Dr. Pia is to divide the compass-card into a limited 

 number (16) of directions and to represent the sum of all the dips attribu- 



