178 Reviews—Professor Suess’ The Face of the Earth. 
But the opposite appears to be the case in regard to the shell- 
.ayer, i.e. of organisms preserved in part as carbonate of lime, for in 
their case aragonite shells, judging from the occurrence of casts, are 
more typical of later than earlier deposits. In this case we must 
remember that the habitat of the animal will influence the replace- 
ment of its shell as calcite or aragonite—in other words, their 
distribution depends in each epoch upon the bathymetrical range of 
the organisms. But that of the crystalline masses of aragonite found 
in caverns and cavities in other rocks depends, according to Wallace, 
upon the water-level and the temperature of springs percolating 
through the superincumbent mass; and in large measure upon the 
former secular heat of the earth’s crust. 
REVIEWS. 
I.—Tue Face or tHe Karta (Das Antlitz der Erde). By Hpuarp 
Surss. Translated by Herrua B. C. Sorzas, under the direction 
of W. J. Sortas. Vol. IV. 8vo; pp. viii, 673, with 55 illustra- 
tions. Oxford: Clarendon Press, 1909. Price 25s. net. 
ITH this fourth volume, which brings the total number of pages 
up to 2233, we have the completion of the text of Professor 
Suess’ great, and we may well say marvellous, work. To ascertain 
what is known of the main features in the structure of the entire 
globe, to systematize that knowledge, to show the influence of 
successive crust-movements on the present features of the earth’s 
surface, is but a bald account of what has been accomplished by the 
author, and admirably rendered into English by Miss Hertha Sollas, 
with the aid of her father. 
Knowledge based on the sedimentary characters and life-history of 
the formations, on the extent of land and sea areas at different epochs, 
and on the influence of volcanic phenomena is fully utilized; but the 
dominant feature in The Face of the Earth is the careful study of the 
earth-movements and foldings to which various districts from time 
to time have been subjected. Some areas, like Laurentia, show little 
or no disturbance since Cambrian times, the strata of that epoch lying 
horizontal, whereas other regions have been affected by more or less 
complex systems of folding at successive epochs, the movements being 
influenced by buttresses of older rocks that have led to deflexion and 
overthrusting. 
In the present volume attention is drawn to the arc-like curves of 
mountain chains, and also to the arcuate lines to be found among the 
Pacific islands, where the greatest abyssal depths, having the form of 
elongated furrows, lie in front of the outer border of the ares. As the 
author remarks: ‘‘ With one or two exceptions, all marine abysses 
which sink below a depth of 7000 meters are fore-deeps in a tectonic 
sense, and indicate the subsidence of the foreland beneath the folded 
mountains. Thus we are brought back to the question, whether the 
greatest deeps, like the highest mountains, are not the most recent.” 
