THE SEARCH FOR ANCIENT LIFE FORMS IN THE 

 ROCKS OF THE WESTERN UNITED STATES 



By CHARLES E. RESSER, 

 Curator of Stratigraphic Paleontology, U. S. National Muscun, 



The geologist, in his endeavors to ohtain the minutiae that will even- 

 tually yield an understanding of the laws of his science, must spend 

 many hours of patient toil climbing steep mountains, penetrating deep 

 canyons, or tramping the bare expanses of deserts. From year to year 

 he must take advantage of favorable weather and of every other oppor- 

 tunity to seek details for completing the picture he is attempting 

 to draw. 



My quest for facts to assist in depicting earth conditions that pre- 

 vailed when the earliest life record was in the making took me over 

 a considerable part of the western United States during the field sea- 

 son of 1930. Two general problems were chosen for attack. In view 

 of the increasing interest of geologists in the earliest forms of life 

 on the earth as well as the role played by algae as rock makers, the 

 purpose of the first explorations of the season was to study the 

 ancient sedimentary rocks exposed in the Grand Canyon of the Colo- 

 rado River. The search for organic remains in these old, relatively 

 unmetamorphosed sediments was particularly desired by Dr. David 

 White, Research Associate of the Carnegie Institution, in conjunction 

 with his studies at the Grand Canyon, and it was through his arrange- 

 ments with the Carnegie Institution and the National Park Service 

 that the trip was made possible. 



The second general field of inquiry to be given consideration was 

 Cambrian geology, in which I am especially interested and which I had 

 previously studied in the Great Basin and the Rocky Mountains to 

 the north. As I had never seen the geology of Arizona, it was with 

 eagerness that I seized the opportunity to make a hurried visit to most 

 of the more important Cambrian exposures in that state. 



In order to do the contemplated work in the Grand Canyon before 

 hot summer weather, I left Washington May 13. At the Grand Can- 

 yon, I found everything in readiness. The party consisted of Dr. A. A. 

 Stoyanow, of the University of Arizona, and myself as geologists, with 

 Ernest Appling as guide and Howard Childers as packer. Upon the 

 arrival of Doctor Stoyanow we immediately crossed the Canyon to 

 the North Rim. We planned to traverse the narrow peninsula which 



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