

CHAPTER XVI 
GEOLOGICAL SURVEYING 
Geological Surveying. Field Equipment. Topographical Maps. Data 
to be Mapped. Various Scales of Maps. Signs and Symbols. 
Tracing of Exposed Outcrops. Tracing of Concealed Outcrops— 
Evidence supplied by Soils and Subsoils, by Vegetation, by Form 
of Surface, by Springs, by Index-beds, by Alluvial Detritus. Carry- 
ing Outcrops across Superficial Formations. 
IT is quite possible to acquire a considerable knowledge of 
Geology by the mere intelligent perusal of text-books. 
Without having engaged in practical work, one may even 
learn to read a geological map, and come to understand in 
a general way the structure of the region it portrays. 
Knowledge obtained after this fashion, however, is necessarily 
superficial, and can never supply the place of personal 
observation or study in the field. It is only after the student 
has familiarised himself with the phenomena themselves, that 
the full meaning of what he may have read about them will 
dawn upon him. The best counsel, therefore, which one can 
give a beginner is to commence observation in the field at 
the earliest opportunity, even before he has gained more 
than a mere elementary acquaintance with the stony science. 
Some preliminary knowledge of common minerals and rocks 
is doubtless desirable, and the student will be all the better 
prepared for his field-work should he have learned to recognise 
some, at least, of the more important type-fossils of the several 
geological systems. Such elementary knowledge, however, is 
not hard to acquire, and the want of it need not deter him 
from beginning the study of rock-structure. A profound 
acquaintance with this important branch of geology has been 
obtained by several noted observers, who could hardly be 
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