110 PECKHAM — THE GENESIS OF BITUMENS. [April i, 



would emerge from the ocean of water heavy with dissolved chlo- 

 rides and sulphates, while an atmosphere dense with carbonic acid 

 would help to maintain a temperature that would retard the cooling 

 through vast cycles of geologic time, in the course of which, under 

 conditions entirely different from any now known, vegetable and 

 animal life would appear upon the earth, or, more properly, in the 

 waters that covered the earth. 



4. It is very evident that the chemical conditions obtaining in 

 this remote geologic epoch, while not incompatible with the 

 development of life, were, however, very different from those which 

 have prevailed at any time since the advent of any of the higher 

 forms of animals. We have a right to believe that at the dawn of 

 life, of all the elements that enter into the composition of vegetable 

 and animal tissue — carbon, hydrogen, oxygen, nitrogen, phosphorus 

 and sulphur — nitrogen alone was wholly free. Carbon and hydrogen 

 existed in combination with oxygen as carbonic acid and water. 

 Phosphorus and sulphur were oxidized, and in combination with 

 basic elements as salts. The excessive proportion of carbonic acid 

 and aqueous vapor in the atmosphere gave to it the property of 

 transcalesence, by which, while readily penetrated by heat from the 

 sun, it refused to transmit this heat when reflected from objects at 

 the earth's surface. This gave to the atmosphere properties similar 

 to those of a greenhouse, by which so high a temperature was main- 

 tained during the coal period that semitropical plants flourished at 

 the poles. At an earlier period, before terrestrial vegetation had 

 removed the carbonic acid from the air, and before the surface of 

 the cooling earth had lost its heat by radiation, the palaeozoic (dawn 

 of life) ocean and the land gave support to both vegetable and 

 animal life, at a temperature that at the present time would destroy 

 most organic forms. ^ 



5. The strata which form that portion of the earth's crust which 

 has been referred to the palaeozoic era, are of enormous thickness 

 and are found in different parts of the world, to present aspects 

 strikingly similar. Messrs. Hall, Billings and Dawson, in North 

 America, Salter and Hicks in England, Angelin in Sweden, and 

 Barrande in Bohemia, have shown that the forms of animal life in 

 that early period were very closely related, if not identical, in these 

 widely separated areas ; yet, below these formations, which hold the 



1 \V. H. Brewer, Am. Jour, Set. (2), xli, 389. 



