41 



ence he will find that he necessarily adopts a system 

 of signs and contractions on his map, not only to save 



^, but to |irc\t-iil the in. !*ing SO OW- 



icd with note* as to become hopelessly confused. 

 lu^t insensibly invents contractions of 

 the fundamental tacts of geological struc- 

 ture, however, it is eminently desirable that the same 

 signs and symbols should be used with the same mean- 

 ing on all published geological maps. The subjoined 

 diagram shows some of the signs used on the maps of 

 ological Survey of Great Hnuin and Ire 





nn 



I Venial 



Strike of ckavff^ 



<f "* 

 > Copp 



Fio. 4- 





