210 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



also for the abrupt bend of the Bear River, since at this 

 point a basalt plain is the only divide between it and the 

 Portneuf, which flows into the Snake, a tributary of the Co- 

 lumbia; into which also the Bear once emptied, but now, 

 reversing its course, flows into Great Salt Lake. 



To the north of this region and of the great basin of the 

 Upper Green, or Colorado River, the geology as w T ell as 

 the topography is more complicated, the country being ex- 

 ceedingly broken, and volcanic and eroding agencies hav- 

 ing been active, botli in long-past and more recent times; 

 but the studies of Messrs. St. John and Endlich, to whom 

 these districts were assigned, have solved many perplexing 

 points, and their evidence will probably determine the re- 

 lations of the principal stratigraphical phenomena to the 

 main mountain chains, and enable us to form decided opin- 

 ions concerning the geological age of the mountains them- 

 selves. 



In addition to these parties covering definite districts, a 

 fifth, under Dr. White, who has succeeded the late Mr. Meek 

 as paleontologist to the survey, was assigned a special duty 

 viz., to endeavor to correlate the scattered stratigraphical 

 observations which have been made by different parties on 

 either side of the Rocky Mountain chain and of the Uintas. 

 With his party he therefore travelled in such directions as 

 would enable him to examine the geological formations in 

 their succession, so as to determine as far as possible the 

 questions which have arisen concerning the limits of each, 

 its correlation with the others, and to define its paleonto- 

 logical characteristics. Such a work must precede any ra- 

 tional classification of the different formations. 



He first traversed in various directions the plains at the 

 eastern base of the Rocky Mountains of Colorado between 

 Cheyenne and Denver; he next crossed the mountains by 

 way of Boulder Pass, the Middle and Egeria Parks, to the 

 head-waters of the Yampa, and passed a short way down that 

 stream. Crossing: the divide between this river and the 

 White, he followed the latter nearly to Utah, then turned 

 northward and crossed the Green River at the southern base 

 of the Uintas, making many detours on the way; skirted the 

 whole length of the Uinta Mountains westward, turned them 

 by twice crossing the Wahsatch Mountains, and then followed 



