XIV 
PREFACE. 
termine. This is especially true of the older crystalline formations, 
which are so extensively developed in this state. The most obscure of 
all the tracts of these rocks is that which was denominated the Salisbury 
and Greensboro Granite by Dr. Emmons; yet, as circumstances have 
necessitated the giving of an almost exclusively practical direction to the 
work of the Survey hitherto, except so far as volunteer work is con- 
cerned, this interesting series of rocks has passed without even a complete 
or systematic reconnoissance. 
This belt of rocks appeared to be sufficiently distinct in some of its 
obvious characteristics from both the Huronian and Laurentian, to justify 
its separation from both (partially) ; and the general outlines given by Dr. 
Emmons have been preserved, as they were confirmed by my own obser- 
vations, made in a number of incidental cross-sections. And in the chap- 
ter of Outlines, besides some observations of my predecessors, its salient 
features are briefly sketched. But Prof. Julien, of Columbia College, is 
now at work upon the series, and it is hoped that his study of them 
from the point of view of lithology, will throw important light on their 
geological relations hitherto set down conjectually. 
The Surface Geology of the state has been studied with much care and 
in considerable detail, but for want of funds for illustration, the discus- 
sion of the subject was restricted to the narrowest limits, as it would 
not be practicable to convey an adequate impression of it without dia- 
grams. It is hoped that this difficulty may be removed in the publica- 
tion of the next volume. 
And, in general , this volume may be considered, in part, as a sort of 
resume' of the whole subject of the geology of the state, as far as worked 
out, the labors of my predecessors being freely used and embodied with 
my own ; and this course seemed the more needful, as the former reports 
of the Survey are out of print, and, from the smallness of the editions 
printed, are little accessible. (And among those who have contributed to 
the general store of information on the subject of the mineralogy of the 
state, besides such as have been officially connected with the Survey at 
various times, there are several gentlemen whose names deserve special 
mention, particularly Gen. Clingman, who has kindly contributed much 
valuable information on the discovery and localities of minerals, acknowl- 
edged in Dr. Genth’s Appendix,— and Dr. C. L. Hunter, of Lincoln 
county, who has made some interesting discoveries of minerals in his 
region, and who also kindly placed his information at the service ot the 
Survey). 
