The Hard Evidence 



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Mark Bothko, Light. Earth and Blue:® 1 994 Artist's Rights Society; Courtesy of C S M Arts. New York 



The awe-inspiring story of the evolution of life on earth is hidden in layer upon 

 layer of sedimentary rocks. Over millions of years, sediments settled into these 

 massive formations, which were compressed and then twisted and deformed by the 



immense forces of plate tectonics. The fossil evidence of life that survived these 



processes is rare and fragmentary. But when — ^with hard, diligent field and laboratory 



work, and luck — scientists do piece together a chapter of life's odyssey, the tale it 



tells rings true because it has the undeniable weight of deep time on its side. 



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