APPENDIX TO THE REPORT OF THE SECRETARY. 



GOVERNMENT EXPLORATIOXS AND SUEYEYS IN 1878. 



The following are brief accounts of the principal explorations of the 

 government in 1878, from which specimens will be derived for increasing 

 the collections of the National Museum. They are furnished by the sev- 

 eral directors of the explorations : 



THE WORK OF THE UNITED STATES GEOLOGICAL AND GEOGRAPHICAL 

 SURVEY OF THE TERRITORIES UNDER THE DIRECTION OF PROF. 

 F. T. HAYDEN DURING THE SEASON OF 1878. 



The work of the survey was intrusted to four parties, viz : One for 

 carrying on the primary triangulatioii ; two parties for geologic and 

 topographic work; and a party for special geologic studies and photog- 

 raphy. These were so organized that in case of necessity they could 

 be divided for special duty. The field headquarters of the survey was 

 at Cheyenne, Wyo., and the outlits and animals were transported via 

 the Union Pacific Railroad to their points of departure. 



Geologij. — Dr. Hayden, the geologist in charge, accompanied the pho- 

 tographic division, and the route pursued gave him an opi^ortunity t& 

 secure a very accurate general knowledge of the geological structure of 

 a large area. The Wind River Range proved one of remarkable interest. 

 It has a trend about northwest and southeast, with a length of about 100' 

 miles. On the west side all the sedimentary belts have been swept away, 

 down to the Archaean, older than the AVahsatch, and the latter formation 

 rests on the Arch^an rocks all along the base of the range, seldom in- 

 clining more than 5° to 10°. On the east side of the range the seams 

 of sedimentary formations usually known to occur in the northwest are 

 exposed from the Potsdam sandstone, which rests upon the xlrchoean 

 rocks, to the Cretaceous inclusive. 



Along the northwestern portion of the range the Wahsatch Group only 

 is seen for some distance, but as we proceed down the Wind River 

 Yalley the formations apjiear one after the other, until at the lower end 

 the entire series is exposed. The Wind River Range may be regarded 

 as originally a vast anticlinal, of which one side has been entirely 

 denuded of the sedimentary, except the Middle Tertiary. On the same 

 side of the range the morainal deposits and glaciated rocks are shown 

 on a scale such as we have not known in any other portion of the West. 

 Three genuine glaciers were discovered on the east base of Wind River 

 and FrtMuont Peaks, the first known to exist east of the Pacitic coast. 

 S. Mis. 59 5 C5 



