THROUGH THE GEOLOGIST'S EYES 



takes on new wrinkles. Just why the earth's crust 

 should wrinkle along lines of rock of such enormous 

 thickness is not a little puzzling. But we are told it 

 is because this heavy mass of sediment presses the 

 sea-bottom down till the rocks are fused by the in- 

 ternal heat of the earth and thus a line of weakness 

 is estabHshed. In any case the earth's forces act 

 as a whole, and the earth's crust at the thickest 

 points is so comparatively thin — probably not 

 much more than a heavy sheet of cardboard over 

 a six-inch globe — that these forces seem to go their 

 own way regardless of such minor differences. 



The Alps and the Himalayas, much younger than 

 our Appalachians, were also begotten and nursed in 

 the cradle of a vast geosyncline in the Tertiary seas. 

 We speak of the birth of a mountain-range in terms 

 of a common human occurrence, or as if it were an 

 event that might be witnessed, measurable in hu- 

 man years or days, whereas it is an event measurable 

 only in geologic periods, and geologic periods are 

 marked off only on the dial-face of eternity. The 

 old Hebrew writer gave but a faint image of it when 

 he said that with the Lord a thousand years are as 

 one day; it is hardly one hour of the slow beat of 

 that clock whose hours mark the periods of the 

 earth's development. 



The whole long period during which the race of 

 man has been rushing about, tickling and scratch- 

 ing and gashing the surface of the globe, would make 



95 



