526 . REVIEWS 



diastrophic movement in Quarternary time, the several retreats and 

 advances of the sea, with the cutting of cHffs ten to twenty miles inland 

 each time; the deposition of hundreds of feet of limestone between 

 uplifts; the carving of deep valleys in the terraces back from the sea; 

 and the fact that while .the cycle of coastal movements is still in opera- 

 tion the amount of movement has been imperceptible in historic times 

 (since the time of the Incas). 



He points out peculiar conditions and processes in the desert at the 

 present time. The work of the sun, slicing the pebbles of the alluvial 

 deposits into thin angular fragments, is shown. The facetting of pebbles 

 by the wind is a common feature, and is carried to the point where, of 

 the original pebbles, small splinter-like fragments alone remain. A t3T)e 

 of stream-lined topography developed by the wind is described. A dis- 

 cussion is given of the sand dunes of the area, in which he presents instruc- 

 tive observations and ideas, stressing the location and shape of dunes as 

 influenced by their function as a filler for dead air space. The discussion 

 of crescentic dunes is of particular interest. 



A section on the Paleontology of the Tertiary formations by Messrs. 

 Woods, Vaughan, Cushman, and Hawkins is the only part of the volume 

 not contributed by the principal author. The Negritos fauna is cor- 

 related with that of the Wilcox and Lower Claiborne groups of the Gulf 

 Coast Eocene; and is also stated to resemble Alpine, French, and English 

 Eocene faunas, pointing somewhat to an Eocene trans-Atlantic ocean, 

 with northern and southern shore-lines. The Lobitos fauna is called 

 upper Eocene, in part at least. A number of excellent plates illustrate the 

 detailed description of the different species. 



The section on the petroleum geology stresses the lack of anticlinal 

 structure, and the absence of oil except in the Tertiary. Surface indica- 

 tions of oil are abundant, such as oil seeps; oil-bearing mud volcanos; 

 petroleum odor, of sandstones particularly; and the presence of petroleum 

 on the sea near by. A large part of the total Tertiary section is pro- 

 ductive at one horizon or another, although few of the sands are con- 

 tinously traceable laterally. Their productivity is highly variable, 

 probably because of the extensive faulting; resulting in moderate sized 

 wells over a large area. There is little or no underground water. 



The character of the oil, which is dark to greenish brown, mixed 

 base, and chiefly from .81 to .85 specific gravity (43.2-35 Be), changes 

 near the old shore-line at the foot of the Andes, where it becomes heavier 

 and more asphaltic. In general the oil gives 15-35 per cent of distillate 

 at 150° C; 30-50 per cent at 150-300°, and good lubricants from the 



