white: relations between coal and petroleum 201 



deposits. Nevertheless, when it is remembered that the organic 

 compounds actually present in coals and bituminous shales are 

 largely undetermined; that the conditions of geologic distillation 

 are fundamentally different from those provided in the labo- 

 V ratory, and that the residues obtained at all stages in the labo- 

 ratory process are widely different from those found in the earth, 

 doubt is cast not only on the assumed similarity in the states 

 and chemical composition of the eliminated matter but also as 

 to whether all the matter is expelled as gases. Furthermore, 

 it is probable that the natural distillates, generated under differ- 

 ent geological conditions (from organic matter which itself may 

 vary widely in chemical composition), vary both as to their 

 chemical compounds and as to their properties far more widely 

 than do the artificial distillates obtained from the same organic 

 deposits. 



Attention has already been given to the differences between 

 the high-oxygen ingredient matter of the typical humic deposits 

 (coals) and the high-hydrogen ingredient material of the typical 

 cannels and oil rocks. Obviously, the volatile matter expelled 

 from the former contains larger amounts of oxygen in some one 

 or more combinations, while the volatile matter from the latter 

 is rich in hydrogen. The reduction of these organic deposits, 

 which intergrade one with another, will be discussed more fully 

 in a later report. The two most important facts to be noted 

 in passing are, first, that coals and oil rocks have yielded ''vola- 

 tile matter" products in different proportions and probably in 

 very different compositions and structures also; and, second, 

 .that in both cases the processes of " devolatilization" result in 

 the reduction of the solid residues through chemical changes 

 that accomplish, in eft"ect, their carbonization. 



. regional alteration of organic debris and corresponding 

 regional differences in petroleums 



Having briefly reviewed some of the effects of regional dynamic 

 influences, principally thrust pressure, in the progressive alter- 

 ation of the carbonaceous residues, represented by coals, oil 

 rocks, carbonaceous shales, etc., we will next inquire whether 



