of the survey, up to the end of the year eighteen hundred and sixty- 

 three, has already been made known in the letters addressed to the 

 Governor from year to year. A resume of the movements of the various 

 parties will also be found in the preface of the first volume of the geology 

 of the report. 



In the summer of eighteen hundred and sixty-four, a small party was 

 fitted out to commence the exploration of the Sierra Nevada, it being 

 my intentibn to work up the geology and topography of that great 

 chain, from the south towards the north, as accurately as our time 

 and means would allow. This party consisted of Messrs. Brewer and 

 Hoffman, accompanied by Messrs. King and Gardner, volunteer assist 

 ants in the geological and topographical departments. They took the field 

 in May, and proceeded across the plains of the San Joaquiri to Yisalia, 

 from which point they entered the Sierra, ascending King's River to 

 its source, and exploring the whole region about the headwaters of that 

 and Kern River. Thence they made their way across the range by a 

 pass over twelve thousand feet high, passed up Owen's Yalley, ascended 

 the west branch of Owen's River, crossing the Sierra again at an alti 

 tude of twelve thousand four hundred feet, and thence descending to the 

 head of the San Joaquin River. The exploration was continued through 

 the region of the headwaters of that stream and the Merced, connecting 

 the reconnoisance with that of eighteen hundred and sixty-three around 

 the sources of the Tuolumne. The whole expedition occupied about 

 three months, during which time the geography and geology of a dis 

 trict including an area of over ten thousand square miles were for the 

 first time explored, the whole region having previously been entirely 

 unknown. The results prove to be of the greatest interest, disclosing 

 the fact that this was the highest part of the Sierra Nevada, and that it 

 embraced the loftiest mountains and the grandest scenery yet discov 

 ered within the territory of the United States. For the details of this 

 reconnoisance reference may be made to Chapter X of Volume I of the 

 Geology, which has just been, published by the survey. 



At the close of this campaign Professor Brewer relinquished his posi 

 tion on the survey, and left California to enter on his duties as Professor 

 in the Sheffield Scientific School of Yale College. He still remains, how 

 ever, charged with the direction of the botanical department of the 

 survey, as will be noticed further on, under the head of botany. 



Messrs. King and Gardner continued their explorations northward of 

 the field of their labor during the summer, by making a survey and 

 map of the Yosemite Yalley, under authority of the Commissioners 

 appointed to take charge of the tracts embracing that valley and the 

 Big Tree Grove of Mariposa County, recently conveyed to the State of 

 California by the United States. 



In the spring of eighteen hundred and sixty -four. Mr. King had com 

 menced the detailed exploration of the principal metalliferous belt of 

 the Sierra Nevada, by examining the geology of the Mariposa estate 

 and its vicinity. This work was continued by Mr. Remond in the 

 summer of eighteen hundred and sixty-five, and carried from the Mer 

 ced to the Stanislaus River, a careful geological and geographical map of 

 that region having been furnished by him as the result of his labors. In 

 addition to this he visited and examined seventy-seven gold mines, 

 besides many other localities of other metals, and sixty-six quartz mills, 

 of which twenty-three were in operation. This work, which is the con 

 tinuation of that done in the Sierra during the previous year, forms the 

 first contribution to our detailed exploration of the mining districts of 



