36 abstracts: geology 



pressure caused by the load of sediments that overHe them, and by 

 the thrusts to which they have been subjected. 



The gas and oil in the De Soto-Red River field were probably accu- 

 mulated under hydraulic pressure. This hypothesis is supported by 

 the relations of these substances to the structure and by the occurrence 

 of the oil in very productive pools of small area. R. W. Stone. 



GEOLOGY. — The Bowdoin dome, Montana, a possible reservoir of oil or 

 gas. Arthur J. Collier. U. S. Geological Survey Bulletin 

 661-E. Pp. 17, with maps, sections, and illustrations. 1917. 

 The Bowdoin dome is situated on Milk River, in northeastern Mon- 

 tana, on the main line of the Great Northern Railway between Malta 

 on the west and Hinsdale on the east. A well drilled here for water 

 several years ago has been yielding a small flow of gas ever since, and 

 it is thought that the region offers a chance of success to the driller of 

 deeper wells. In 1915 a large gas well was drilled at Havre. Only the 

 Upper Cretaceous Claggett shale, Judith River formation, and Bear- 

 paw shale, and some of the more recent surficial deposits are exposed 

 in the immediate vicinity of the Bowdoin dome. The structure revealed 

 by the Judith River formation in its outcrop around the valley of Milk 

 River is that of a very broad, flat dome. The dips of the sandstone 

 are so low as not to be detected by the unaided eye and are best re- 

 corded in feet to the mile. There is no place around the dome where a 

 dip as high as 1 degree has been found. 



The Bowdoin dome has a structure which if found in Oklahoma or 

 Ohio would be regarded as favorable for the accumulation of oil or gas. 



R. W. Stone. 



GEOLOGY. — The Corsicana oil and gas field, Texas. George Charl- 

 ton Matson and Oliver Baker Hopkins. U. S. Geological 

 Survey Bulletin 661-F. Pp. 43, with maps, sections, and 

 illustrations. 1917. 

 The Corsicana oil and gas field, in Navarro County, Texas, measures 

 20 miles from north to south and 10 miles from east to west. Oil was 

 first discovered here in the city of Corsicana, and the field has been 

 productive for more than twenty years. 



The oil and gas are obtained from the upper part of the Upper 

 Cretaceous, the light oil and the gas in the Corsicana oil pool and in the 

 Chatfield and Edens gas pools probably coming from the Taylor marl 

 and the heavy oil and the gas in the other pools from the Navarro 



