PREFACE. 



The examinations authorized were entered upon soon after the passage 

 of the resolution, and continued until the 28th of November, comprising 

 a period in the field of about six months. The first five weeks were 

 occupied in examinations of the more elevated and western portions of 

 the Counties of Butte, Sierra, Yuba, Nevada and Placer, in determining, 

 as far as possible, the position of an ancient water course in this section 

 of the State, and its peculiarities the description of which will be found 

 in the body of this report. 



On the 23d June, the southern portion of the tour was commenced, 

 and carried on almost uninterruptedly for four months. The route south 

 was carried through the Counties of San Francisco, Santa Clara, Santa 

 Cruz, Monterey, and the north part of Luis Obispo ; on the west, and 

 returning on the east, (or through that range denominated the Monte 

 Diablo Eange) by the west part of Tulare County, Mariposa, Tuolumne, 

 Alameda, Contra Costa and San Joaquin. 



The range of country bounded on the north by the Straits Carquinez, 

 and south by the Nacismiento, was divided into four sections, formed 

 by lines running nearly east and west from the great valley to the 

 coast. On the first of October, the country north of the Straits Carqui 

 nez was entered, and preliminary examinations only were made in the 

 counties of Solano, Napa and Sonoma, From the County of Napa a 

 section was carried across the basin of the Sacramento, and connected 

 with, examinations made two years previous on its eastern edge. A sim 

 ilar section was also made, passing eighteen miles south of Monte Diablo 

 and continued across the San Joaquin. 



The remainder of the months of October and November was employ 

 ed in investigations of the middle mining sections of the County of Ne 

 vada and those intermediate between the former and the middle and 

 western parts of Calaveras county. This range leads through that sec 

 tion in which the principal gold mines of the middle portions of the 

 State are located, and was selected, with the view of conducting those 

 examinations which will be found in the appendix of this report, under the 

 head of Quartz Mining. As those mines have of late presented many in 

 teresting facts connected with their ultimate prospects, a set of sketches 



