REVIEWS 309 



surprisingly conformable to the present topography, being high on the 

 divides and low near the valleys." It probably will be correlated with 

 some portion of the Seymour formation in Wichita County, Texas 

 which is referred to the Pleistocene. The suggestion is made that the 

 Grandfield conglomerate may not be a stream deposit. 



Quaternary gravels, alluvium, dune sand, and soil mantle the older 

 consolidated deposits. 



The general structure of the Permian strata is based on the exposures 

 of the Augur conglomerate. The most important structure is the 

 southeast-northwest trending Devol anticline which crosses the district. 

 To the north and parallel to this lies the Deep Red syncline. Minor 

 anticlines and synclines are present. About one-half of the report is 

 devoted to "detailed stratigraphy and structure of the exposed rocks 

 by townships." 



In the adjacent portion of northern Texas are located the Petrolia, 

 Burkburnett, and Electra oil and gas fields. The "sands" are of 

 Pennsylvanian age. Since similar beds evidently underlie the Permian 

 in the Grandfield district, and since the structure of both places is com- 

 parable, the existence of commercial pools in the Grandfield district is 

 very probable. Suggestions as to the location of test wells are given. 

 The opinion is expressed that "accumulations of oil and gas in pools is 

 due to the action of large bodies of water moving under both hydraulic 

 and capillary pressure." 



V. 0. T. 



Relation of the Wissahickon Mica-Gneiss to the Shenandoah Lime- 

 stone and to the Octoraro Mica-Schist, of the Doe Run-Avondale 

 District, Coatesville Quadrangle, Pennsylvania. By Eleanora 

 F. Bliss and Anna I. Jonas. A dissertation (Bryn Mawr 

 College). Pp. 64, pis. 5. 

 The authors conclude "that the Wissahickon mica-gneiss [pre- 

 Cambrian] is separated from the Shenandoah limestone [Cambro- 

 Ordovician] and from the Octoraro mica-schist [Ordovician] by a thrust 

 fault, which has been obscured by post-Ordovician metamorphism." 



V. 0. T. 



