314 Dr. Carl Oclisenhis — On Mefalli/erous Deposifs. 



yet nearly sufficient to produce the second deposit of carbonate of 

 lime. It occupies only about 24-5°/o (specific gravity 1-107) of the 

 volume of pure sea water, so that still further reduction down to 

 ]9°/p (specific gravity 1-1304:) is required before the second deposit 

 can take place. If carbonates of soda were formed in the neigh- 

 bourhood of the Great Salt Lake from limestone formations and salt 

 matter, then these must have been drained into the lake and would 

 be found in its waters, or at any rate in the mineral springs of the 

 neighbourhood. This, however, is not the case, and no carbonate of 

 soda at present exists there. With reference to this CI. King says : 



" Along the base of Wahsatsch Range at Salt Lake City and north 

 of Ogden, are important hot springs pouring a large volume of 

 heated waters into the lake drainage. They contain sulphuretted 

 hydrogen, carbonates of lime and magnesia, sulphate of soda, and 

 chloride of sodium, the latter being in all cases much the largest 

 factor. From a qualitative examination of numerous salines, besides 

 those whose quantitative analyses are given in the accompanying 

 table, it seems that the predominant salts of this whole basin are 

 chlorides of sodium and magnesium, with sulphates of soda, lime, 

 and potash, the latter always in much less quantity than the chloride 

 salts. The efflorescence at the sink of Deep Creek is the only alkaline 

 carbonate observed ; and even if in the localities not visited by us 

 there should be found other sources of alkaline carbonates, they 

 ruust remain as exceedingly unimportant and exceptional salts in this 

 basin." (40th Par. vol. 1. p. 500.) 



Now no carbonate of soda exists in the district of the Great Salt 

 Lake although so plentiful in the neighbourhood of the rich soda 

 basin of Lahontan in Nevada, and this surprising circumstance, which 

 King looks upon as difficult to explain, is very intelligible if a glance 

 be given at the map No. vi. in the first volume of his work. In the 

 whole region of the Great Salt Lake, only two trachyte masses of 

 any importance exist, that of Clayton's Peak and the less important 

 mass through which the Jordan flows. Beyond these in the whole 

 of the immediate drainage-region of the Lake there are only the 

 insignificant trachyte mountains to the south of the Utah Lake in 

 the neighbourhood of the watershed, and isolated basalt cones 

 scattered about. The Lahontan Basin lying westward with its many 

 lakes is rich in carbonate of soda, and is in striking contrast to the 

 absence of this salt in Utah. The cause of this great difference 

 between the two basins arises from the fact, that the Lahontan 

 district is covered with innumerable volcanic upheavals of basalt, 

 rhyolite, trachyte, dacite, andesite and propylite. The salts which 

 came into contact with them were formed from the same mother 

 liquor as in Utah; the only difference being, judging from their 

 comparatively large proportion of borates, that in Nevada the 

 mother liquor existed perhaps in a more concentrated state. Many 

 isolated eruptions created large areas of disturbance and large 

 quantities of cai'bonic acid, the latter forming with some of the 

 mother liquor salts carbonates of sodium. This has been the case 

 not only in the west of the United States, but also in all cases where 



