REPORT OF THE SECRETARY. 71 



field chart of the county. Later in the season be discovered, in Haw- 

 kins County, Tennessee, some very interesting cave deposits, which he 

 carefully studied and from which large collections were sent to the 

 office in Washington. From this point, in October, he went southeast- 

 wardly through Hawkins County, studying the formations on the way, 

 and by the last of the month was at Knoxville, where he examined the 

 rocks of the Potsdam deposits, to supplement Mr. C. D. Walcott's 

 work. The work in the vicinity of Knoxville and Centerville was con- 

 tinued through the latter part of the year, although bad weather in- 

 terfered considerably with his work. 



District of the Rocky Mountains. — Work in this district, under the 

 charge of Mr. S. F. Emmons, was begun early in July. Mr. Whitman 

 Cross was assigned to work in the Silver Cliff region. The report on 

 this region will be of value from the fact that it is a camp of abortive 

 processes, a true history of which will serve as warning by pointing 

 out the errors which caused the failures there. Work was continued in 

 this region through July, August, and part of September. Mr. S. S. 

 Sackett was detailed to gather statistics as to reduction works in 

 the district. A short trip was made to the Sangre de Cristo Range, on 

 the opposite side of the valley from Silver Cliff, to determine the geo- 

 logic relations of the rocks of this range to the Silver Cliff deposits. 

 Work in the Denver coal basin was begun, but had to be stopped be- 

 fore the end of the season. Some attention was paid to the subject of 

 artesian wells, and the material obtained will be embodied in the re- 

 port ou the Denver basin. In the office the notes on the ten-mile dis- 

 trict were worked up, a geologic map and sections were prepared, and 

 lithological determinations were made preliminary to final elaboration 

 and publication. Messrs. Cross and Chapman have been engaged in 

 the preparation of geologic maps, and some field work was done by Mr. 

 Cross in the vicinity of Golden and Morrison, on the Mesozoic rocks 

 which are exposed in this region. 



Yellowstone National Pari: — Mr. Hague began field-work in the Yel- 

 lowstone Park in the latter part of July. His investigations were mainly 

 confined to a preliminary examination to ascertain what the geologic 

 problems really are. The Upper and Lower Geyser Basins were visited 

 in August, and a geologic reconnaissance was made from the Upper Basin 

 to Shoshone Lake of the Heart Lake Basin, for the purpose of comparing 

 them with the Upper Basins of the Firehole, and to ascertain what thermal 

 and other changes have occurred since 1878. Mr. Hague thinks that 

 Mount Sheridan is a volcanic crater, so modified by glacial action as to 

 practically obscure its true origin. A collection of 200 specimens of gey- 

 serites was carefully made for the educational rock series. In September 

 permanent camp was established near the Great Valley of the Yellowstone, 

 and short trips were made into the adjacent region. The Mount Wash- 

 burne group was examined, and the headwaters of the Gardiner and 

 Gibbon Rivers and the region of the Grand Canon were visited. The 



