FOSSIL FOOD 277 



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good many other things in solution in sea water besides, 

 gypsum and common salt ; such as chloride of magnesia 

 sulphate of potassium, and other interesting substances 

 with pretty chemical names, well calculated to endear them 

 at first sight to the sentimental affections of the general 

 public. These other by-contents of the water are often 

 still longer in getting deposited than common salt ; and, 

 owing to their intermixture in a very concentrated form 

 with the mother liquid of the Dead Sea, the water of that 

 evaporating lake is not only salt but also slimy and fetid to 

 the last degree, its taste being accurately described as half 

 brine, half rancid oil. Indeed, the salt has been so far 

 precipitated already that there is now five times as much 

 chloride of magnesium left in the water as there is common 

 salt. By the way, it is a lucky thing for us that these 

 various soluble minerals are of such constitution as to be 

 thrown down separately at different stages of concentration 

 in the evaporating liquid ; for, if it were otherwise, they 

 would all get deposited together, and we should find on all old 

 salt lake beds only a mixed layer of gypsum, salt, and other 

 chlorides and sulphates, absolutely useless for any practical 

 human purpose. In that case, we should be entirely de- 

 pendent upon marine salt pans and artificial processes for 

 our entire salt supply. As it is, we find the materials de- 

 posited one above another in regular layers ; first, the 

 gypsum at the bottom ; then the rock-salt ; and last of all, 

 on top, the more soluble mineral constituents. 



The Great Salt Lake of Utah, sacred to the memory 

 of Brigham Young, gives us an example of a modern 

 saline sheet of very different origin, since it is in fact not 

 a branch of the sea at all, but a mere shrunken remnant 

 of a very large fresh-water lake system, like that of the 

 still-existing St. Lawrence chain. Once upon a time, 

 American geologists say, a huge sheet of water, for which 



