ACADEMY OP NATURAL SCIENCES. 375 



most mineral countries. Here it will probably hereafter be detected in our 

 micas, and perhaps in other combinations, and also in mineral and sea water; 

 but its most abundant source, fluor-spar, seems entirely wanting in this State. 



Bismuth is another element of common occurrence in various combinations, 

 but it has not yet been detected in California. A few minute scales of a min- 

 eral that I determined to be bismuth-silver, from the Twin Ophir mine, Nevada, 

 is the only authentic instance I know of thus far, of the occurrence of this ele- 

 ment on the Pacific coast. Tungsten, uranium and vanadium, are tolerably 

 widely disseminated ; the latter, however, less so than the former. No trace of 

 either has yet been found on this coast north of Mexico ; of strontium, zirconium, 

 aud glucinum, the same may be said. If we now compare the distribution of the 

 elements in the South American Andes with that on this coast, we shall find 

 some striking points of resemblance ; and to a large extent, either the absence, 

 or else the great rarity of several of the elementary substances not seen in 

 other mineral regions, is a fact which hohls good along the whole extent of the 

 American Continent on the Pacific side. Fluorine, in combination with cal- 

 cium, is almost as rare in Peru, Bolivia, and Chile, as on this coast. Indeed, 

 it was formerly supposed by Domeyko not to occur at all in Chile, but 

 recently one or two localities, where it is found in small quantity, have been 

 made known. Tungsten occurs in Peru at one locality in the form of wolfram, 

 and in Chile in one or two localities, also in Lower California, but its combina- 

 tions are extremely rare along the whole coast. The same may be said of 

 uranium. Strontium and zirconium have not yet been discovered in Chile or 

 Peru, although the former occurs in one locality in New Grenada, and gluci- 

 num has only recently been found in Chile in very minute quantity in one local- 

 ity. No combination of lithium is yet known on the Pacific coast. 



Among the leading facts connected with the occurrence of mineral substances 

 and the elementary bodies on the Pacific coast, and especially in the Cordilleras 

 of North and South America, the following may be mentioned as generally 

 applicable to the whole of the vast region extending frem British Columbia to 

 Chile : 



1st. The paucity of species considering the extent of the region as compared 

 with other parts of the world, and especially with other mineral regions. 



2d. The remarkable absence of the prominent silicates, and especially of the 

 zeolites. 



3d. The absence of a large number of the elementary substances, and the 

 paucity of several others of very common occurrence in other mineral regions. 



4th. The very wide spread and abundant occurrence of the precious metals, 

 gold and silver, and the not uncommon occurrence of platina. 



5th. The great abundance of ores of copper, aud the comparative absence of 

 tin, lead, and zinc. 



6th. The similarity in the mineralized condition of the silver — antimony and 

 chlorine being prominent mineralizers of this metal — while in Chile the rarer 

 combinations of iodine, bromine, aud selenium occur, these latter being as yet 

 unknown north of Mexico. 



7th. The absence or paucity as veinstone, or gangue, of one of the most 



