Reviews—Die Sulfid-Srlrikatschmelzlosungen. 87 
The volume also contains somewhat detailed accounts of two 
special features of much interest, the Paisley Ruck and the Thick 
Cpal of Quarrelton. The Paisley Ruck, although a leading tectonic 
feature, appears not to have been hitherto described. It is essentially 
a crush-zone or shatter-belt, of generally anticlinal form, beginning 
on the north side of the Clyde near Drumchapel, and extending 
south-westwards, past Paisley and Johnstone, and through the 
Lochwinnoch gap into Ayrshire. Within this zone, which is from 
150 to 200 yards broad, the strata are extraordinarily broken and 
contorted, while the edges are as a rule sharply defined by faults 
with varying displacement. Near Linwood the throw of the fault 
on the northern side is at least 1,800 feet, though usually much less. 
The Thick Coal of Quarrelton appears to be formed by the local 
coalescence of several seams, and has a normal thickness of nearly 
50 feet. But there are also at least two cases of local “* doubling ”’ ; 
in one of these the enormous thickness of 100 feet of coal, or coal 
with thin clay partings, is attained. It is shown that the thick 
seam was originally laid down against a steep slope of the underlying 
lavas, and that the duplication was caused, not by overthrusting but 
by a contemporaneous process analogous to a bog-slide. This fact 
seems to have some bearing on current discussions as to the origin 
of ‘‘ wash-outs ”’ in other coalfields. 
Ree aR: 
Die SuLFID-SILIKATSCHMELZLOSUNGEN, |: Drie SULFID-SCHMELZEN 
UND DIE SULFID-SILIKATSCHMELZEN. By J. H. L. Voer. 
Vidensk. Selsk. Skrifter, I Mat.-nat. Klasse, 1918, No. 1. 
132 pp., with 45 text-figures. Kristiania, 1919. 
Din SuLFIp-SILIKATSCHMELZLOSUNGEN. By J. H.L. Voer. Norsk. 
Geol. Tidsskr., vol.iv. 97 pp., with 13 text-figures. Kristiania, 
GIA. 
a two publications contain the results of researches under- 
taken by Professor Vogt during the last few years on the 
physical chemistry and mineralogy of the sulphides and their 
relations to silicate melts, with special reference to the slags obtained 
in the smelting of copper matte. The first-named and larger work 
forms a third part of Professor Vogt’s well-known work Die 
Silikatschmelzlisungen ; the second contains a summary of the results 
set forth in the larger volume, published at an earlier date owing 
to difficulties encountered on the production of the complete 
work under war conditions. We are also informed in a preface 
that another memoir is in preparation dealing specially with the 
nickeliferous pyrrhotite ore-bodies, which are here only referred to 
incidentally. The publication of this will be anticipated with much 
interest by all mining geologists. Professor Vogt also states that 
he has in hand a nearly completed work on crystallization and 
magmatic differentiation in the basic intrusive rocks. 
