310 proceedings: geological society 



through the sediments, so that sea water, which was interstitially 

 included in marine sediments, has probably undergone a like mode of 

 concentration. 



Judging from experimental results obtained with illuminating gas, 

 methane should be no exception among gases in its capacity to take 

 up and transmit moisture. The amount of moisture in a given volume 

 of gas under any given conditions can be calculated from the vapor 

 pressure of solutions of salt in water. Conditions favorable for the 

 transmission of water as vapor in porous rocks may be created by the 

 chemical production of gases, by the expansion of compressed gases, 

 by the release of gases held in solution in oil or water by pressure, 

 and by the vaporization of liquefied gases. 



Salt and brines are commonly found near occurrences of gas and 

 petroleum, so that gases may have been effective in the evaporation 

 of the solutions which yielded the salt. In fact, salt domes may be 

 the result of evaporation and crystallization brought about by the 

 passage of expanding natural gas which has carried off moisture as 

 vapor and possibly also has cooled the solutions from which salt was 

 crystallized. 



The great changes effected in the waters of the Appalachian fields 

 during the production of oil and gas were explained in part by the 

 mode of occurrence of oil-gas-water mixtures in this region of low 

 dips. The occurrence of gas and oil overlying water was attributed 

 in part to induced segregation brought about during movements 

 through the pay sands after production was begun. 



M. I. Goldman: Results of the microscopic examination of some rocks 

 from the oilfields of southeastern Ohio. This is a preliminary study and 

 the conclusions are therefore only tentative. The primary object of the 

 investigation was to find any characters of the rocks that might bear on 

 the distribution of oil in them. As the work progressed it appeared that, 

 in addition, light might be thrown on some of the early stages of meta- 

 morphism and their relation to geologic conditions It was found imprac- 

 ticable to make determinations of pore space because, by the tearing out 

 of soft minerals, and in other ways, holes are produced in grinding the 

 thin section. The investigation was therefore limited to the study of 

 epigenetic minerals. The following were recognized: Quartz as a 

 secondary growth around the original grains and in continuous crystal- 

 lographic orientation with them, was found in almost all not too argil- 

 laceous sandstones. The approach to quartzite was in general greatest 

 in the deepest beds, though this factor was very variable. Kaolinite 

 in fine crystalline aggregates filling the pore spaces. This is known as 

 a common mineral in sandstones. Calcite and other carbonates. 

 These seemed to be particularly abundant in older fields or fields in 

 which wells were very numerous, thus indicating a relation to recent 

 circulation of ground, waters resulting from the drilling. Sulphides 

 (pyrite or marcasite) were scarce in this field and occurred mainly in 

 the clays associated with carbonaceous matter, a common syngenetic 

 relationship. It is significant, however, as illustrating the mineralogic 



