alternation is independent of the thickness of any one section. If a well does 

 not penetrate the entire interval, an alternation rate can nevertheless be deter- 

 mined for the portion of the section drilled. Table 24-11 illustrates the application 

 of this principle. 



It is evident that the rate of alternation is independent of the thickness of 

 the interval; for example, in well 1 the rate is 16 changes in lithology per 500 

 feet of section. If the section were 1000 feet thick, there would be 32 alter- 

 nations; but the rate would remain the same, as would the value plotted on the 

 map for contouring. 



Figure 24-37. Map showing clastic percentages in solid contours and clastic ratios in 

 dashed contours. Clastic ratio of 1.0 = 50 percent. 



496 



