760 REVIEWS 
of itself cannot fail to impress the reader with a sense of the abundant 
store of facts from which M. Lacroix has drawn his interesting and even 
startling conclusions. These refer to the prime topics of exomorphic 
and endomorphic metamorphism and the mzse en place of the gran- 
ite, on all three of which the investigations of M. Lacroix shed new 
light. 
The granite occurs in the form of a broad stock stretching some 
50°" from east to west, and the bulletin refers particularly to the con- 
tacts atthe westernend. The rock is a normal coarse-grained granitite, 
sometimes, though never at the contacts, charged with phenocrysts of 
microcline several centimeters long. At the contacts it is filled with 
an extraordinary number of inclusions of the country rocks. 
The latter are composed of slates and quartzites with non-magnesian 
limestones, either massive or interrupted with interbedded slaty layers. 
All of these rocks have been affected, often profoundly, by contact 
metamorphism. To this cause is to be attributed the development of 
a micaceous character, with garnet, cordierite, and sillimanite common 
in the contact belt. But the most important determination of this new 
crystallization is that of the existence of orthoclase and of the triclinic 
feldspars in the micaceous slate zone (/epf¢ynolites) in amounts which 
make the feldspar, either the predominant constituent or less abundant, 
even to its appearing only as scattering grains. This feldspathization 
has occurred by the process of ‘‘imbibition”’ or by the injection of 
minute granite apophyses 4¢ par “it. The quartzites are similarly 
feldspathized and rendered micaceous, though in less marked degree 
than the slates. The white and black limestones, on the other hand, 
are much more affected, containing grossularite ( gvenazzte), vesuvianite, 
various pyroxenes and amphiboles, epidote (¢fzdo#zte), and the triclinic 
feldspars from oligoclase to anorthite (Cornéennes feldspathiques). 
Marmorosis is common. On p. 48, M. Lacroix has given a clear state- 
ment of the theory of feldspathization and of the part played by the 
agents minéralisateurs in the recrystallization of metamorphic belts. 
As is well known, he is at one with MM. Fouqué, Michel Lévy, Barrois 
and others who contend for an actual migration of granite substance 
from an intrusive granite stock in the presence of mineralizing agents, 
into the country rock, as well as for the possible removal of certain ele- 
ments in the exomorphic contact zone under the same conditions of 
intrusion. A detailed argument for this position is given in Chapter 
III; its analysis would be beyond the scope of this review. 
