RIVER OF LIFE 55 



bottom waters of the Black Sea are lacking in oxygen as a 

 result of conditions set up by its isolation, so were the waters 

 of some of those bygone inland seas. 



Under ordinary conditions the organic remains in sediments 

 are oxidized and their chemical energy is lost, so that they are 

 no longer able to change into oil-producing materials. In the 

 Black Sea today, though, due to the lack of oxygen there is a 

 great increase of bacteria of a special type, and it is these reduc- 

 ing bacteria that bring about a chemical transmutation in the 

 deposits. One effect of this alchemy is to make the bottom 

 waters poisonous to other forms of life; but another effect is 

 to start the sediments along the long chemical road which 

 leads to petroleum. The same lack of oxygen that is believed 

 to be so important in the early development of oil-producing 

 sediments is also found in some of the limestone muds form- 

 ing today beneath the waters of the River as they circulate in 

 the Gulf of Mexico. Francis Shepard, submarine geologist of 

 the Scripps Institute of Oceanography, and his associates, have 

 begun a detailed study of such deposits in the western part of 

 the Gulf, and the limestone sediments around the Florida Keys 

 are being studied by marine scientists at The Marine Labora- 

 tory in Miami. It is likely that these studies of the sea floor 

 will throw new light on the ancient alchemy that brought oil 

 to the sediments of hundreds of millions of years ago. 



The principal oil fields of North America were mostly 

 formed in the later Paleozoic period, before the Appalachian 

 mountain uplift, and again before the rising of the Andes and 

 Rocky Mountain systems, and especially during the past 40 

 million years which we call the Tertiary. The later Paleozoic 

 fields are the final chemical result of plankton which lived in 

 seas covering parts of Pennsylvania, the midcontinental area 

 of Kansas, Oklahoma, and Texas, and parts of Illinois, Indiana, 

 and Kentucky. On the other side of the River and during the 

 same period similar deposits were being formed in England 



