U. H. tiEOLOGICAI. SURVEY 



J>ROFEaSIUNAL PAPER 129 PLA.TB Tl 







7Cf- 



60- 



50- 



20"- 



10- 



a- 



2(f- 



3Cf- 



2 I 



40^- 



50'- 



60°- 

 7(f- 

 90*^ 



.i S 



N " 



< 9 



Index figure, showing use of chart 



Angle of slope Cc-sca/e; 0°20°30° 40° 50° 60° 65° 70° 75] 



Angle of dip (3 scale) sdzcf 60° 50 40° 30 ^ ^ 25^ 20 15 



INSTRUCTIONS 

 Traco values of angle of slope and angle of dip to an intersection 

 in the network. Conni'Ct value of 'I with this intersection by 

 a straight line. Uhing eithrr a .straii;htr<i(je or a transparent 

 atraight-Ii'ne index, and continue the line to intersect tlieC 

 scale. Connect intersect i')n on (' scale with value of slope dis- 

 tance by another straight line, and continue theiine to inter- 

 sect the thickness scale. This lait intersection will give the 

 required value of thickness of strata. 



-700 



-800 



200 



AI.INKMENT CHART FOR GRAPHIC COMPIITATION OF THICKNESS OF STRATA. 



