172 abstracts: geology 



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GEOLOGY. — The Helderherg limestone of central Pennsylvania. John 

 B. Reeside, Jr. U. S. Geological Survey Professional Paper 108-K. 

 Pp. 41. 1917. 

 A study of seven localities in Pennsylvania leads to the following 

 conclusions : 



1. The Tonoloway limestone and the Keyser, Coeymans, and New 

 Scotland members of the Helderherg limestone may be traced from 

 Maryland through central Pennsylvania with their respective char- 

 acteristic lithology and faunas, and the essential equivalents of all are 

 to be found in New Jersey and eastern New York. 



2. The Kej'ser member decreases in thickness northward from 

 Maryland. 



3. The Devonian elements in the fauna apparently decrease from 

 Maryland to New Jersey and New York. 



4. The • suggestion of an unconformity at the top of the Ke3'ser in 

 Maryland is borne out in Pennsylvania by the variations in thickness 

 of the member and the presence of arenac'eous material at the base of 

 the Coeymans. R. W. Stone. 



GEOLOGY. — Geologic structure in the Gushing oil and gas field, Okla- 

 homa, and its relation to the oil, gas, and ivater. Carl H. Beal. 

 U. S. Geological Survey Bulletin 658. Pp. 64, with maps, sections, 

 and illustrations. 1917. 

 The geologic work done in the field has disclosed the following 



principal facts: 



1. The folding of the formations in the Gushing field usually becomes 

 greater with increase of depth, and there are many marked differences 

 in structure among the Layton, Wheeler, and Bartlesville sands and 

 the surface beds. 



2. The interval between the Layton and Bartlesville sands is gen- 

 erally greater around the edges of the anticlines than on their crests. 



3. The distribution of the bodies of oil, gas, and water indicates 

 that the source of the oil lay west of the Gushing field. 



4. In general the oil area in an elongated dome, where folding is 

 simple, extends farther down on the long axes of the anticline or dome 

 than on the steeper sides. 



5. The water surfaces on which the oil and gas rest in the different 

 sands are not level but are inclined away from the centers of the anti- 

 chnal folds. R. W. Stone. 



