Mineralogy and Geology. 119 
at that office in regard to the geography of the State. The maps, as thus 
blocked ouit, have been np by us in the field, by filling in the topography 
wherever our route has lai 
The maps which have a or are now being prepared for publica- 
tion are: 
Ist. A map of the vicinity of the Bay of San Francisco, on a scale of 
half an inch to the mile, four feet by three; it extends from near Santa 
Cruz on the south to Napa on the north, and from the Pacific to Corral 
Hollow, east and west. The area of land which it covers is 4,248 square 
miles, which is just twice that of the State of Delaware, and only lacks 
and has about thirty inhabitants to the square mile—the average density 
of the age of California being but little over two to the square mile. 
is map, on which all the details of the topography are given, as 
minutely as the scale allows, is nearly completed, and will be soon ready _ 
for the engraver. 
2d, A detailed map, on a scale of two inches to the mile, of the 
vicinity of Mount Diablo; this is about two and one-half by three feet 
in dimensions, and includes the most important coal mining district yet 
own to exist in the State. The map can be made ready for the en- 
graver in a few days. 
map of the Coast Ranges, from the Bay of Monterey south to 
Santa Barbara. It is about three feet by two and one-half in dimensions, 
is on a scale of six miles to the inch, and embraces about 16,000 square 
tuiles of territory. To ponies it will require about another year’s work 
in the field with two sub-part 
Map of the Washoe silvettolnkos region—three and one-half by 
two and one-half feet in dimensions, on a scale of two inches to 
mile—and extending over fis the important mining ground of the district. 
This map is from an accurate trigonometrical survey by V. Wacken- 
reuder ; it is nearly sie 
5th. Ma ap of the Comstock Lode, on a scale of four hundred feet to the 
inch, completed. 
6th. Map of the central portion of the Sierra Nevada; scale not ye 
determined on. Extensive surveys have been made r. Wackenreuder 
for this vase of the work, and these will be continued during the present 
above mentioned maps, Nos. 1 and 2 will accompany the first 
iets of the Report. Nos. 4, 5, and probably 6, the second volume. 
It is intended, if the survey is carried to completion, to construct a 
final map of the 'State on a — of six miles to the inch, in nine sheets, 
each about three feet squar 
In addition to the Sra topographical work, an extensive series of 
barometrical observations has been made, for the determination of alti- 
_ tudes, and some two hundred and ey important points have been as- 
cended and measured. The most interesting operation in this Tietanenk 
_ Was the determination of the height of Mount Shasta, which, by an elabo- 
_ Yate series of observations, we found to be 14,440 feet above ‘the sea level, 
_ This is the first of the lofty voleanic peaks of the Sierra Nevada which 
_ has been accurately measured. 
