ABSTRACTS OF PAPERS 101 



were quickly redeposited in the form of liydrou.s calcium cai'bo-phosphates, 

 locally filling, incrusting. and replacing shells, teeth, bones, etcetera, but espe- 

 cially forming oolithoid granules of colophanite, and finally a phosphatic 

 cemont among all the particles. The granular texture is ascribt^d chiefly to 

 physico-chemical conditions like those which result in oolithoid greenalite, 

 limonite, aragonite, etcetera. After having been formed in quiet water, some 

 of the granules were reached by bottom-scouring currents and incorporated in 

 clastic deposits, and in some instances were even strewn over eroded rock 

 surfaces, and so became constituents of basal conglomerates. 



One of the chief outstanding pi-oblems relating to the origin of the western 

 deposits is the nature of tlie environment capable of supplying the inferred 

 successive layers of animal carcasses. This calls for more exact paleogeo- 

 graphic data than are now available, although plausible suggestions may be 

 presented. Other problems lie in the domain of sea-bottom physics and chem- 

 istry and relate to the exact cycle of changes between dissolved apatite washed 

 in from the land and the final precipitation of colophanite on the sea-floor. 



Presented by title in the absence of the author. 



REGIONAL ALTERATION OF OIL SHALES 

 BY DAVID WHITE 



(Abstract) 



The examination of "oil rocks," such as cannels anil lichly l)ituminous 

 shales which yield petroleums on distillation, lying in or beneath coal-bearing 

 formations, shows that the organic matter of the shales, etcetera, is, in general, 

 regionally altered and carbonized together with the coals, the alteration of the 

 organic debris by the dynamic agencies being parallel in both. A study of the 

 distribution of petroleums and their salient features seems to show that: (1) 

 No commercial pools of oil are to be found in regions where the coals in or 

 above the oil-bearing formations have reached the stage of carbonization at 

 which the fixed carbon (proximate analysis) exceeds 75 per cent of the pure 

 coal, though gas pools diminishing in importance may lie l)oyond ; (2) in re- 

 gions of complete anthracitization the carbonaceous matter in the associated 

 shales is correspondingly fixed; (3) the oils of pools in regions of relatively 

 high fixed carbon in the rocks are, in general, highest in saturated hydrocar- 

 bons, and so highest in hydrogen and lowest in gravity; (4) in passing into 

 zones of successively lesser alteration of the organic debris the oils are of 

 lower rank and the unsaturated and lieavier hydrocarbons are, on the whole, 

 more and more in evidence, the lowest grades of oils being found in forma- 

 tions in which the solid fuels are lignitic in rank; (5) while the residues of 

 the organic debris are progressively altered, with the elimination of oxygen, 

 nitrogen, and hydrogen, with some carbon, to composites progressively richer 

 in carbon, the liquid distillates in the rocks as the alteration advances be- 

 come richer in hydrogen — that is, while the carbonaceous n>sidues in the rocks 

 ])CCome more distinctly caiiioniz(>d their li(|uid liyrlrocaibon distillates iioconio 

 more fully hydrogenizod, the processes being in a way comiilcinentary. 



Occurrences of abnormally high grade oil in low grade regions are probably 



