274* ^^^ POPULAR SCIENCE MONTHLY. 



silica, woTild go on tiiitil the affinities of the acids were satisfied, 

 and there would be a separation of silica taking the form of 

 quartz, and the production of sea- water holding in solution, be- 

 sides the chlorides and the sulphates of sodium, calcium, and 

 magnesium, salts of ammonium and other metallic bases. The 

 atmosphere, being thus deprived of its volatile chlorine and sul- 

 phur compounds, would gradually approximate to that of our 

 own time, but would differ in the greater amount of carbonic-acid 

 gas." 



And the meteorologist Abbe, in the course of remarks made 

 before the Philosophical Society of Washington in 1889, express- 

 ing the propriety of wholly rejecting the idea that the earth was 

 once a molten globe, stated : " The study of geological climate 

 during and since the formation of Azoic metamorphic strata has 

 led me to adopt the conclusion that surface geology, like volcanic, 

 does not demand excessive temperatures ; it seems to me most 

 reasonable to assume that the surface was never much warmer 

 than 250 F., but to allow that this temperature may have pre- 

 vailed at the close of the Archaic epoch. 



" At this temperature all the water of the ocean would exist 

 only as vapor and clouds in the atmosphere. The steady, hot rain 

 from the atmosphere would rapidly disintegrate the surface rocks. 

 Small seas and lakes of water saturated with alkalies and salts 

 would at once begin to form the rocks that we know as metamor- 

 phic and archsean. The covering thus formed would contribute to 

 diminish the rate of cooling of the interior mass, thus allowing 

 the atmosphere to cool down to its present condition and deposit 

 the most of its moisture." 



In the rocks formed earliest after Archaean time, to which geo- 

 logical age only crystalline rocks devoid of fossils belong, there 

 are found aquatic relics of organisms with calcareous skeletons 

 which when living bore a close generic relation to organic forms 

 which are confined to oceanic waters at the present time. Among 

 these early inhabitants of the sea were corals, crinoids, sea urchins, 

 and starfishes, and many others there doubtless were which, al- 

 though they require the saline constituents of the sea to live upon, 

 had no calcareous skeletons, and consequently have not been pre- 

 served in a fossil state. The remains are found deposited in the 

 lower Silurian as well as the Devonian, Carboniferous, Jurassic, 

 and Cretaceous formations. 



But apart from these deductions concerning the saltness of the 

 primeval ocean there is direct evidence that the waters of the sea 

 in the early part of Paleozoic time were highly saline, for there 

 were deposited from the waters of the Silurian sea saliferous 

 strata which constitute the Onondaga salt group and the Trenton 

 and Chazy limestone series, in which the relics of marine organ- 



