FK RY TRAVERSES 49 



scale of fix inches e, with which the field-work 



is now chiefly conducted, admit of almost unlimited 



detail important or interesting stratum may be 



put down and traced on these maps; little dislocations 



of only a few t may be shown even when 



they arc pretty closely crowded together ; no feature of 



geological value need be omitted for want of space to 



>s it A it ions of intricate and detailed 



geological mapping I may cite Sheets 19, 75, 96, and 



101 of the one-inch Geological > -;land 



-Vales; and Sheets 14, 15, 22, 23, 91, 101, 107, and 



f Scotland. The six-inch maps of the coal-fields, 



published by the Survey, should also be examined 



Now with field-geology and m .4 as possible, 



and as actually accomplished, in Britain, let us contrast 

 the conditions under which work of this kind must be 

 carried on in an unexplored region like the Western 

 Territories of the United States. The survey of vast 

 tracts in those parts of the North American continent 

 iyden, King, and Powell proved them to be among 

 the most zealous, active, and efficient geologists who ever 

 undertook the task of pioneering through a new country. 

 But the utmost skill and experience cannot alter the 

 natural features of a country and its climate. These 

 ys had to be carried on in a very different 

 manner from those of the British Isles, and I cite them 

 as an excellent example of how field-geology can be 

 prosecuted in new and previously unmapped regions. 



As the topographical map of the country required to 

 be made, I >r Hayden's survey was at once geographical 

 and geological His staff contained more topographers 



