Review of Recent Geological Literature. 388 
Id the case of the volcanoes of great hight the composition of the rock 
is most uniform. With the exception of five which consist of leucitic 
and phonolitic rocks, all the others are composed of a pyroxene an- 
desyte and of basalt, with their transitions, and of a little obsidian and 
pumice as acid products. The basic rocks sometimes contain hornblende 
but very rarely become true hornblende andesytes. The pyroxene an- 
desytes contain regularly more of .hypersthen6 than of augite, while in 
the basalts augite displaces hypersthene. '"It is worthy of remark that 
throughout Java the pyroxene andesytes are found conjointly with the 
basalts, but we were not able to prove in any case that these different 
products issued from the same crater. On the contrary in most places 
it is possible to prove with certainty that the pyroxene andesytes, desti- 
tute of olivine, and the basalts, rich in olivine, issued unquestionably 
from different craters.'" This fact and others mentioned by the authors 
show that the "volcanoes of Java do not all derive their issue from the 
same reservoir, but that they are rather openings of separate small foy- 
ers which retain lavas in different states of acidity, some basalts, others 
pyroxene andesytes and still others a mixture of these two or transition 
rocks. The products of the same crater differ, aside from texture, more 
or less in a low content of olivine. For example, the central crater of 
Krakatoa has constantly supplied pyroxene andesyte:the lateral crater, 
of which the peak of Krakatoa properly speaking forms a part, has sup- 
plied basalt." 
The authors find that although the island of Java has been the scene 
of constant eruptive activity from the Eocene to the present there are 
two periods marked by greater energy. The first coincides with the op- 
ening of the Miocene, forming extensive sheets of andesyte, and the 
second at the close of the Teritary, and prior to the present, therefore 
in the Quaternary. Then were formed, for the most part, the numerous 
volcanic summits of Java several of which at the present time rise to 
3000 or more metres above the sea. They consist, for the major part, of 
andesyte and of basalt in the form of slightly coherent materials and of 
lava flows; and exceptionally also of leucitic and phonolitic rocks, which 
had already appeared to some extent in the Tertiary. 
The authors describe the formation of gravels and levigated powders, 
derived from these rocks at the shores, and the microscopic remnants of 
the plagioclase, leucite, augite, magnetite and olivine in the resultant 
rocks, (Vol., I, p. 68) — a process which is supposed to have taken place 
widely in the production of the greenstones of the Archean. 
Notwithstanding the extent of time and the volume of the Java erup- 
tions the authors do not find the law of Iddings exemplified in the suc- 
cession of the deposits, but rather such a melange of basalt and ande- 
syte that no general order of acidity is discoverable. 
The volumes are illustrated by numerous heliotype landscape scenes, 
and by eleven plates principally of fossil Foraminifera. 
The grand atlas which accompanies the work embraces (1) a large ge- 
ological map with a scale 1:200,000 in 20 sheets.. (2) Synoptical map with 
a scale 1:500,000 in 2 sheets. (3) 21 sheets of special areas, different scales. 
