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text, and is in many respects a work of much broader scope than the title 
indicates. 
As stated in the preface, the petrography was chiefly the work of Lewis, 
and the mineralogy was in charge of Pratt. Other portions of the work 
are the result of collaboration, and there was a constant interchange of 
all manuscript for criticism and revision. The individual work of the 
authors was done, for the most part, at different times and places, each 
working independently. Notwithstanding this fact, each was led to essen- 
tially the same conclusions in regard to the origin and relations of both 
the peridotites and corundum. Concerning corundum in the basic magne- 
sian rocks, very similar, and in some respects supplementary, hypotheses 
were deduced by the one from a study of the mines in the peridotites and 
by the other from the petrology of the corundum-bearing amphibolites 
and anorthosites. (Cf. pp. 144 and 344.) 
A brief sketch of the geology of the state is given in chapter i, with a 
somewhat fuller account of the belt of gneisses, granites, and schists con- 
stituting the rugged mountainous section in which the peridotites and the 
corundum deposits occur. 
Chapter ii deals with the peridotites and the associated basic magne- 
sian rocks. ‘These include four varieties of peridotite, four pyroxenites, 
four gabbroic rocks, an amphibolite, and three diorites. These are chiefly 
well-known types. An exception is the pyroxenite composed of the ortho- 
rhombic pyroxene, enstatite. This rock occurs somewhat commonly 
throughout the region, and forms many masses of considerable extent. 
The name enstatolite is proposed for this type, in conformity with the terms 
“‘bronzitite” and ‘‘hypersthenite.” All of these rocks are shown to be 
a part of the great series of basic magnesian rocks which extends through- 
out the whole length of the eastern crystalline belt from central Alabama 
to the Maritime Provinces of Quebec, and again reappears in Newfound- 
land. ‘Together they constitute a petrologic unit of remarkable persist- 
ence and uniformity of characters and association. 
Maps show the distribution and relations of these rocks to the crystal- 
lines in eastern North America and in western North Carolina, besides 
several detailed maps of portions of the belt of particular interest. The 
contoured geological map of western North Carolina (Plate II) is the 
largest and most detailed yet published of this region. The scale is eight 
miles to the inch and the base is printed in three colors. On this the pre- 
Cambrian gneisses and schists and the Cambrian (?) metamorphic sedi- 
ments are represented by tints, while the peridotite dikes and localities of 
corundum, chromite, and asbestos are shown in bright red. 
