34 WAITING IN THE WILDERNESS 



long past of the earth the wash of running water 

 rivers deposited deltas in the sea and in 

 lakes made sedimentary deposits. The delta 

 material changed in the sea to rock. These 

 rocks, if placed layer or strata upon one another, 

 would be forty miles thick. The lower fifteen 

 miles were deposited before any life was upon 

 the earth. These lower are without fossils. 

 From, say, the sixteenth mile to the top where 

 we now are, there are fossils in each layer. Sup- 

 pose we divide these twenty-five miles of layers 

 into one hundred stages of life. The bottom 

 which holds the few oldest fossils we will num- 

 ber One, and the top stage where we are we will 

 call number One Hundred. 



"The advanced and peculiar stage of develop- 

 ment shown in these animals of the Oligocene 

 would, I think, justify their having number 

 Ninety-five. Untold millions, and perhaps bil- 

 lions of years and countless influences had slowly 

 shaped them into what they were. 



" There were but few kinds of fossils in the 

 remote times of number One. These were of 

 small, crude, though simple pattern. Having 

 seen one of this pattern it would never be con- 

 fused with the pattern or model of number Ten 

 or some later times. In a way the fossil model 

 of each age is as distinct and peculiar as that 

 living fossil the Australian duck-bill. The dis- 



