107 



beds appear horizontal. 1 tiling, find any 



actual section along Uu : dip, we should so 



place ourselves as to have *ed edges of the 



strata runmnj in horizontal bare in front of u*. We may 

 then take the direction of dip with the compass, and 

 deter i n the mean of a numU-r of observations 



taken with the clinometer on ^ ledges what most 



>>e the general average angle of dip, The best measure- 

 ments of the angle of dip are made when we can place 

 ourselves some little distance in front of a face of rock 

 i has been cut in the 1 1 n of dip. We can 



.lace the . front of our eye, and make 



its edge coincide with the line of a particular stratum 

 many yards in extent. Thus in one single observation 

 we obviate the risks of error where only small ledges of 

 lined beds can be used. Where the true dip 



meaturing the 



apparent . > faces of rock inclined at a consider- 



able angle to each other, obtain the true dip by calcula 



ascertained these particulars, we insert the in- 

 formation in our note-book or map. The use of a map 

 for the registering of ol> on geological stn. 



es on amount of precision which might not be 

 thought needful for the pages of a note-book, and secures 

 in consequence the most careful and exh. nd of 



field-work. I shall, therefore, suppose in what 1 li. 



> Rules are given far measuring or calculating the dip. (See 

 Green's GffJjgy, p. 461.) For almost all practical purposes, how- 

 ever, a goal gist can get his angle with th 



;tg, as he learns how to do, hi* points of 



