calls which have for the last four years been made upon them, and it is 

 probable that this map. will be put in hand immediately. 



The preparation of a map of the whole State, on a scale of six miles to 

 the inch, was formerly contemplated ; but of later years we have con 

 sidered that this was an undertaking of too extensive a character to 

 meet with encouragement from the Legislature. Should the survey be 

 continued for three or four years longer, we should be able to furnish a 

 general map of California on a scale of ten or twelve miles to the inch, 

 which would far surpass in value and accuracy anything now existing. 

 Still, many years must elapse before correct maps of the almost unknown 

 southeastern and northwestern corners of the State will be had. It is 

 certain that the United States Land Office surveys of the southern part 

 of the State do not give any idea of its topography, and it is difficult to 

 understand how the town and section lines can have been run there, and 

 so little idea of the topography obtained; while the extremely rough 

 and mountainous character of Del Norte, Humboldt, and Trinity Coun 

 ties, now to a large extent in possession of hostile and warlike Indians, 

 will render it difficult to execute any detailed geological or geographical 

 work in that region, for a long time to come. 



II. PHYSICAL GEOGRAPHY. 



Our materials in this department are constantly accumulating; but 

 we have not yet began to arrange them for publication. The baro 

 metrical measurements of mountains have been continued, and instru 

 ments have been carried to greater heights than ever before were 

 attained within the limits of the United States. We await with much 

 interest the elaborate report of Colonel R. S. Williamson, of the United 

 States Engineers, to the Topographical Bureau, on the subject of the 

 laws governing the fluctuations of the barometer on the Pacific coast. 

 This work will be of great importance to science, and of especial value 

 to us, as enabling us to *use our own observations more intelligently than 

 would be possible unless we had the means of carrying on a series of 

 investigations similar to those of Colonel Williamson, and on which a 

 large amount of time and labor would have to be expended. The 

 subject of the distribution of the forest vegetation of the State will 

 occupy a chapter in our volume of Physical Geography, and it is hoped 

 that we shall be able to illustrate it with a map showing the range of 

 the different groups of species. 



III. GENERAL GEOLOGY AND PALAEONTOLOGY. 



The volume just issued, which is entitled "Geology Volume I; a 

 report of progress and synopsis of the fieldwork from 1860 to 1864," 

 will be a sufficient exhibit of our progress in the investigation of the 

 geological structure of the State. 



It is to this department of. general geology that up to the present 

 time by far the greater portion of our attention has been given, since 

 the first thing required in a geological survey is a knowledge of the 

 general geological structure of the State, the age of the various forma 

 tions which occur in it, and their range and extent, or the position which 

 they occupy on the surface, and their relations to each other. Each 

 group of strata, thus determined by its lithological peculiarities, and by 

 the fossils which it contains, is then to be laid down upon the map in 

 the position which its outcrop occupies on the surface. The general 



