328 Reviews—Prof. Grubennmann—The Crystalline Schists. 
material make up 275 feet, while the other half is too earthy and 
impure to be marketable. There is a difference in the colour of the 
Kohat salt and that raised in the Salt Range, and this circumstance, 
so far as.it goes, is rather against the theory of the Tertiary age of the 
famous salt beds near Kheura. 
Gem-stones.—This subject, so interesting to the mineralogist, is 
apparently of little consequence from an economic point of view, since 
there is no tabular statement of value beyond that given for the rubies 
of Burma. The mining for gem-stonesis a matter of history, especially 
in the case of the diamond. The localities for this appear to be 
confined to the Purana group of rocks, and are three in number. 
Probably the most famous is that of the Mahanadi valley, in the 
eastern part of the Peninsula, where stones of great value have been 
found formerly in the alluvium, but not in the older rocks. In the 
Vindhyan conglomerates of Central India the diamond occurs as a sort 
of pebble near Panna, and the diamond-mining industry is stated to 
persist still in this area. No results are given, but we can believe that 
there may be a sort of underground passage for some of these gems, 
whose discovery is not recorded on the spot. During the past six years, 
we are told that the ruby-mining industry in Upper Burma has under- 
gone a favourable change; but, on the whole, it seems to us that even 
this is disappointing, considering the great expectations at one time 
formed on the annexation of the country. Other gem-stones, such as 
sapphire, spinel, beryl, tourmaline, garnet, etc., are noted in small 
quantities. On the other hand, the amygdaloidal flows of the Deccan 
trap furnish, either directly or indirectly, a considerable number of 
agates, whilst the jadeite of Upper Burma has really become an 
important industry. This jadeite is obtained partly in the form of 
pebbles and partly by quarrying. In the latter case ‘‘the jadeite 
forms a layer in the dark-green serpentine, against which, on a fresh 
surface, it stands in striking contrast on account of its light colour. 
The serpentine is apparently intrusive into Miocene sandstones, and the 
jadeite must have been separated as a primary segregation from the 
magma,’’? N.B.—The jadeite of China is described as a silicate mainly 
of alumina and soda, of high specific gravity and great hardness, whilst 
jade is a more basic silicate of magnesia and lime. Thus it is singular 
that the jadeite of Burma should be associated with such a magnesian 
rock as serpentine, and its composition may differ from that of China. 
Wak Be 
IJ.—Crystattine Seuists. 
Diz Kristartiven Scurerer. Von Dr. U. Grusenmawn, Professor der 
Mineralogie und Petrographie am Hidgendssischen Polytechnikum 
und an der Universitat Zurich. I. Allgemeiner Teil, mit 7 Text- 
figuren und 2 Tafeln, 93” x 6”; pp. vi+106. Berlin, 1904, 
M 38:40, bound. IT. Specieller Teil, mit 8 Textfiguren und 8 Tafeln ; 
pp- vui +176. Berlin, 1907, M. 9-60, bound. 
al Le first of these volumes opens with a historical sketch followed 
by chapter A (22 pages) on the original material of crystalline 
schists and its specific characters. The characters of sedimentary and 
