10 



Although the proportion of these various solids might 

 be thought to vary beyond all hope of satisfactory com- 

 parison, upon studying the solid formations of the Dead 

 Sea coast, the differences are greatly lessened. 



The extraordinarily large proportion of chloride of mag- 

 nesium in the Dead Sea may be owing to the indefinite 

 quantity that these very dense salt waters are capable of 

 holding in a state of mechanic^ suspension, and to the 

 absence of organic life, which in the ocean is constantly 

 secreting this solid matter into solid masses. It is certainly 

 true, that magnesian limestone and gypsum are found as- 

 sociated with rock salt here, as they are all over the world, 

 and that the position of the limestone formations of the 

 Dead Sea indicate their deposit when its waters stood at 

 a much higher level than they do now, or that they took 

 place when they were nearly if not exactly upon a level 

 with ocean waters, and were similar if not identical in 

 (Composition, and the existence of marine polyps to create 

 such matter was undoubted; and such deposits continued 

 as long as other conditions permitted the continuation of 

 the existence of this organic life, ceasing only with its ex- 

 tinction. 



The excess of chloride of calcium, as well as the small 

 proportion of sulphate of lime, may be accounted for by 

 the same absence of organic life from the period of the 

 supersaturation of the Dead Sea with chloride of Sodium. 

 This supersaturation being relieved by solid deposits when- 

 ever it became excessive — the enormous deposits upon the 

 Dead Sea shores show why the proportion actually exist- 

 ing in the water is so much less than that of the mag- 

 nesium. 



If the saline deposits of the continents bear such un- 

 equivocal testimony to the decrease of general evaporating 

 surface, the fresh water lakes should add their more meao-re 

 evidences in proof of the same fact. 



The North American and other lakes do show higher 

 water lines than those forming at present, and lacustrine or 



