72 REPORT OF THE SECRETARY. 



bottom of the Grand Canon was reached at four different points. A 

 reconnaissance was made to Steamboat Point on Yellowstone Lake, and 

 Mount Chittenden, one of the highest peaks in the vicinity, was ascended. 

 During this time a study of the geysers in the Upper Geyser Basin was 

 contiuued by Mr. Hague's assistant until September 25, when the camp 

 there was broken up and a new camp was established at Mammoth Hot 

 Springs. From this a trip was made to the western limits of the Park 

 over the summit of the Great Plateau and back via Madison Caiion, 

 where a fine section of rhyolitic rocks is exposed. The region north of 

 Mount Holmes, on the west side of the Park, was also examined, but 

 the results were meager on account of the severity of the storms. A 

 geologic reconnaissance was also made via the East Fork of the Yel- 

 lowstone to the headwaters of Soda Butte Creek and the Clark's Fork 

 mines. Although the country was covered with snow, the work accom- 

 plished was of great value for general geologic purposes, and especially 

 as suggesting plans of operation for next season. About the middle of 

 October the weather became so inclement that the parties were obliged 

 to leave the field. Mr. Iddings was sent to Eureka, Nev., to make col- 

 lections of rocks for the educational series. He secured sufficient ma- 

 terial for 200 cabinet specimens of five characteristic rocks. Three 

 of these illustrate igneous rocks from the Great Basin, and two belong 

 to the supplementary series. "All will be described in the Geology of 

 the Eureka district." 



District of the Pacific — Survey of the Quicksilver District. — Mr. G. F. 

 Becker, who is in charge of the division of the Pacific, has been engaged 

 in the examination of the quicksilver deposits of California. During 

 the early part of the season he carried on an investigation in the vicin- 

 ity of the Sulphur Bank, California. A trip was made to the North Fork 

 of Cache Creek and Tulare Lake, the only localities in this section where 

 fossiliferous strata occur. The early part of September was spent on 

 the North Fork of Cache Creek, and the map of the Clear Lake region 

 was completed. Returning to Sulphur Bank, soundings of the lake 

 were taken, and careful examinations made of the mines. The party 

 then proceeded to San Francisco to prepare for the winter's work, which 

 consists of the revision of Mr. Curtis's memoir of the Eureka mines, the 

 arranging of the Clear Lake and Sulphur Bank collections, and analy- 

 ses of the minerals, rocks, and waters collected, and the general routine 

 of office duties. 



Work was undertaken during the season by Mr. Turner, in the re- 

 gion of Knoxville, but was interfered with by his sickness, which obliged 

 him to enter the hospital at San Francisco. 



Volcanic rocks. — Capt. C. E. Dutton, who has charge of the investiga- 

 tion of the volcanic rocks of the division of the Pacific, has been busy 

 most of the year with the completion and preparation for jmblication 

 of his memoir on the Hawaiian volcanoes, which were visited by him 

 for the purpose of studying the features and processes of volcanoes in 



