4 SMITHSONIAN INSTITUTION 



west of the Grand Canyon village. Extremely high temperatures and 

 the driest season in 50 years rendered this phase of the work some- 

 what difficult, but the beauty of the night sky made us forget the 

 heat of the day. 



The major objective for the season's work lay in the Wasatch 

 Mountains and the ranges of western Wyoming and southern 

 Montana. For the first time I saw the beautiful Green River Lakes 

 region in western Wyoming. Green River, the major branch of the 

 Colorado, flows out of beautiful glacial lakes, and the branches 

 feeding the lakes flow through lofty mountains in gigantic glacier-cut 

 valleys. Granite spires and cliffs of sedimentary rocks rise 3,000 feet 

 above the lake level. Here we found that both the Middle and Upper 

 Cambrian were represented by only about a thousand feet of strata. 



When the Wasatch Mountains were reached, it was gratifying to 

 find that Dr. J. S. Williams, of the Utah Agricultural College at 

 Logan, Utah, had already solved the problems that I had in mind. 

 Accordingly, after a few days in the heat, dust, and smoke it was 

 possible to continue to the Teton and southern Montana ranges. 

 After studies near Logan and in the Beartooth Mountains of Mon- 

 tana, nearly a week was spent studying the Cambrian strata of the 

 Black Hills. 



From early July until Labor Day forest fires were burning on 

 every side and interfered somewhat with the work. With the driest 

 season on record, rivers and streams were reduced to about one- 

 fourth their normal volume, and the wind constantly raised great 

 dust clouds. Temperatures were high, even at night. 



Since my last visit to the Rockies 10 years ago, great changes have 

 taken place. Old camp sites are gone, their places being taken by 

 picnic grounds and cabins, and where formerly one rarely encountered 

 another person, there are now hundreds. More than 60 miles from 

 the highway one finds paths worn in the grass along the stream 

 banks by hopeful anglers, so that even the trout are now few. 



Cambrian rocks are seldom highly fossiliferons. Enormous masses 

 of sediments were deposited in those ancient seas, which we are sure 

 were full of living organisms. For, aside from the evidence furnished 

 by the nature of the sediments themselves, broken fragments of ani- 

 mal remains, scattered everywhere, show that life existed but that 

 conditions were not favorable for its preservation. Occasionally, 

 however, local conditions were such that waves did not break all the 

 shells into fine bits and entombment was rapid enough to prevent 

 decay. There we find beautifully preserved fossils, and it was our 

 good fortune to locate several such spots this summer. 



