TIME AND CHANGE 



the Andes, the Himalayas, he knows they are young, 

 mere boys. When they get old, they will be cut 

 down, and their pride and glory gone. A few more 

 of these geologic years and they will be reduced to 

 a peneplain, only their stumps left. This seems 

 to hold truer of mountains that are wrinkles in the 

 earth s crust squeezed up and crumpled strati 

 fied rock, such as most of the great mountain- 

 systems are than of mountains of erosion like 

 the Catskills, or of upheaval like the Adirondacks. 

 The crushed and folded and dislocated strata are 

 laid open to the weather as the horizontal strata, 

 and as the upheaved masses of Archaean rock are 

 not. Moreover, strata of unequal hardness are ex 

 posed, and this condition favors rapid erosion. 



In imagination the geologist is present at the 

 birth of whole mountain-ranges. He sees them ges- 

 tating in the womb of their mother, the sea. Where 

 our great Appalachian range now stands, he sees, 

 in the great interior sea of Palaeozoic time, what he 

 calls a &quot;geosyncline,&quot; a vast trough, or cradle, being 

 slowly filled with sediment brought down by the 

 rivers from the adjoining shores. These sediments 

 accumulate to the enormous depth of twenty-five 

 thousand feet, and harden into rock. Then in the 

 course of time they are squeezed together and forced 

 up by the contraction of the earth s crust, and thus 

 the Appalachians are born. When Mother Earth 

 takes a new hitch in her belt, her rocky garment 

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