GEOLOGY. 255 



general direction. Gold has been found at intervals from Canada to 

 Georgia, a distance of 1,000 miles, and although insignificant in quan- 

 tity, as compared with California, it occurs under the same conditions. 

 Prof. R. was of the opinion that the amount of gold obtained in Cal- 

 ifornia will greatly decline after a few years. Prof. Sedgwick con- 

 tended that the age of the rock was not a constant phenomenon in 

 connection with gold, but that the condition of the rocks did appear to 

 be constant. Prof. S. disputed Humboldt's generalization upon the 

 direction of the auriferous chains, which he said was no more north 

 and south in most cases than mountain chains run mostly north and 

 south. Sir H. de la Beche thought that gold was not found as had 

 been stated by Sir R. I. Murchison in the older paleozoic rocks only, 

 but that it depended more on mineral and physical conditions than on 

 the age. 



Sir R. I. Murchison then replied, showing that the theories of those 

 who differed from him with regard to the greater abundance of gold 

 at the surface than in the veins, differed from every practical man on 

 the subject ; they differed also in regard to the fact, that the hill 

 ranges were from north to south more than to the equatorial line. 

 This was so in all cases in which large quantities of gold were found, 

 although some modification might be necessary as related to small 

 quantities. London Athenccum, Sept. 22. 



ANALYSIS OF CALIFORNIA GOLD. 



THE following interesting account of an analysis of the gold- 

 en spangles or sands of California was read by M. Dufrenoy before 

 the Paris Academy of Sciences. The spangles of gold of Califor- 

 nia are much larger than those which come from the washings of the 

 Ural or those of Brazil. They also differ in their reddish color, 

 which causes them to be distinguished readily at first sight. Accord- 

 ing to an accurate analysis, their composition is, 



Gold, ..... 90.70 



Silver, ...'.. 8.80 

 Iron. . . . . . . 38 



Total, . . . 99.88 



The soils of the Sacramento valley are light ; to the touch they ap- 

 pear soft enough, but on rubbing, a fe\v particles of a hard substance 

 are felt. Their color is light brown ; the microscope shows them to 

 be almost entirely silicious ; the little fragments of which they are 

 composed are angular and transparent ; easily conglomerated together ; 

 resemble in their color and transparency a saline mass ; nothing but 

 distinct grains are distinguished by the naked eye. A piece of gold 

 sent to " L'Ecole des Mines," weighing 47.9414 grams (nearly 1 J oz.), 

 is of a somewhat red color, its composition otherwise analogous to 

 that of the spangles. This piece of gold adheres to some white 

 quartz, the surface of which is worn like a pebble ; nevertheless it 

 preserves its original form, which is that of a thick vein, flat and ir- 

 regular. The form of this piece, and the presence of the quartz, re- 



