APRIL 21, 1923] 
NATURE 
own 
No 
—O 

ary time a duration of at least five million years, which 
seems an over-estimate. In all probability the rise 
of the land has not been continuous, but rapid move- 
ments of elevation have alternated with long ages of 
quiescence, while the occasional periods of submerg- 
ence may be explained by a slow continuous rise of 
the ocean level, such as is believed by Daly to have 
taken place in the Pacific. It is worthy of note that 
there appears to be no evidence of any renewal of 
compression since that to which the mountains owed 
their formation in late Cretaceous or early Eocene 
times. This suggests a doubt as to whether the west- 
Fic. 2.—‘‘ Rabo de Leon" growing among blocks of quartzite in the Ametape Mountains 

is described ; but it is unfortunate that in deference 
to the wishes of the International Petroleum Company 
of 
“With the exception of a few general comments, 
no detailed account the main oil-field is given. 
sanctioned by the Company, the development and 
conclusions of the past eight years are excluded from 
this description.’ Considering how much the great 
industrial organisations owe to science, one would 
expect from them a little generosity, even a little 
sacrifice of material advantage, if such be required, 
that they may repay their debt to research by adding 
their quota to the general fund of human knowledge. 

(Vhe height of these plants here is about 3 feet.) 
From *‘ Geology of the Tertiary and Quaternary Periods in the North-west Part of Peru,” 
ward movement of South America, postulated by 
Wegener, can have continued far into Tertiary times. 
There is not space to follow the author in his descrip- 
tion of the climatic conditions in the desert ; of the 
effects of the rare torrential rains and the slow desicca- 
tion that succeeds; of the deeply cut valleys, the 
breccia fans, and the valley and marine terraces ; of 
the work of sun and wind, and of the scanty animal 
and vegetable life ; except to say that the book should 
take its place beside the writings of Walther and Cloos 
in the libraries of all students of the desert. 
The concluding chapters contain a useful account 
of the petroleum deposits of the area, in which oil- 
wells have been sunk to a depth of 4ooo feet. Valu- 
able information is afforded as to the stratigraphical 
range of the oil, and the history of its exploitation 
NO. 2790, VOL. 111] 

It only remains to state that the book is excellently 
illustrated by numerous sketches and reproductions 
of photographs (two of which are given here) and 
by clearly-drawn maps, plans, and sections. 
Joun W. Evans. 

Our Bookshelf. 
Aspects of Science. By J. W. N. Sullivan. 
(London: R. Cobden-Sanderson, 1923. 
Most works on that department of thought which lies 
on the frontier between philosophy and science should 
be included by pharmacologists among the class of 
narcotic drugs. As narcotics they are very effective, 
for they induce oblivion rapidly and profoundly, and 
they have the great advantage of being without any 
of the undesirable—or other—after-effects that are 
Pp. 191. 
6s. net. 
