CHAPTER IV 



GEOLOGICAL MAPS 



IN the foregoing list of a field-geologist's accoutrements, 

 the map was put first. The propriety of assigning it 

 this place of honour will be admitted when the 

 meaning and importance of a geological map are recog- 

 nised, and when the observer can carry with him the 

 map on which he himself has traced the geological 

 boundary-lines. A published geological map is a valu- 

 able guide when it can be had, but in the field-geologist's 

 eyes its importance is but secondary compared with the 

 map which contains perhaps the substance of his work 

 for weeks or months together. 



The results obtained by the geologist in the field, from 

 his investigation of the rocks, may be set down either in 

 writing, or in maps and sections. No one can follow the 

 practical pursuit of the science without being conscious 

 how much his work gains in precision when he is com- 

 pelled to put it down upon a map. Not only is his 

 information made more accurate, when he requires to 

 trace the exact lines of geological boundary, but he is 

 led to search in nooks and corners, of which he would 

 not otherwise have suspected the existence, and thus he 



