6 



eighteen hundred and sixty-six; but, in addition, there was considerable 

 field and office work done, chiefly of a topographical character. Mr. 

 Wackenrender was in the field in May and June, mapping the country 

 between the Sonora and the Big Tree roads, across the Sierra Nevada. 

 Mr. George H. Goddard plotted for this survey a large amount of work 

 done in previous years at the head of the Mokelumnc, Stanislaus, and 

 American Eivers. He also plotted a considerable area along the eastern 

 boundary of the State, including part of the White Mountain range. 

 Mr. E. D'Heureuse commenced the survey of Kern County, on his own 

 account, which work he was unable to finish, and which was therefore 

 ti>rned over to us on payment of a small portion of its cost, with the 

 understanding that he should go on to complete it during the next year, 

 at the expense of the survey. Mr. S. F. Peckharn, in May and June, 

 made a special detailed examination of all the important oil-bearing 

 localities, or those which were reputed as such, for the purpose of secur 

 ing a supply of material for chemical examination, and to obtain informa 

 tion in regard to the economical value of the bituminous substances of 

 that region. 



During the winter of eighteen hundred and sixty-six and sixty-seven, 

 Mr. Gabb was detached from the survey, and accompanied by Mr. F. 

 Yon Lbhr, made a survey of the Peninsula of Lower California, for pri 

 vate parties. The scientific geological results of this expedition, which 

 were of veny considerable value, as giving the first clue to the structure 

 of an extensive and important region, were communicated to and will 

 be published by the California Academy of Sciences. 



The chemical examination of the bituminous products collected during 

 the season was carried on at Boston and Providence during the ensuing 

 winter, by Mr. Peckham, for the term of six months, and the results 

 obtained by him will be embodied in the volumes of economical geoloiy. 



The fieldwork of this year (eighteen hundred and sixty-six) was pro 

 longed until late in the season, and as early as possible the next year it 

 was resumed, as will be seen from the following synopsis : 



FIELDWORK OF 1867. 



1. Mr. Hoffman, with Mr. A. D. Wilson as assistant, commenced 

 March sixth, to work up the region of the foothills between the Chow- 

 chilla and King's Eivers. May twentieth 1 joined the party, and we con 

 tinued the surveys to the Big Tree grant and across the Yosemite to 

 Coulterville. where the party was broken up, Mr. Hoffman returning to 

 San Francisco to go on with the office work. Mr. W 7 ilson was then 

 joined by Mr. Von Lohr, and they proceeded to make a survey of the 

 Calaveras Grove of Big Trees on their way to the road across the Sierra, 

 via Placerville. 



2. Mr. Gabb, accompanied by Mr. E. E. Poston, about the middle of 

 June, joined Messrs. Wilson and Lohr, and they together proceeded to 

 the eastern border of the State for the purpose of making the necessary 

 surveys to complete the southeastern sheet of the Central California Map. 

 Of this party, a portion of the expenses was paid by the United States 

 and apart by myself. Only that was charged to the State of California 

 which was justly due for work done within its limits. This party, after 

 exploring the White Mountain range, carried their work east ;>s far as 

 the one hundred and sixteenth meridian, working up the geology and 

 topography of an extensive region very difficult to explore, and one in 



