Geology and Mineralogy. 393 



thus shown the actual occurrence of the two reactions specified, 

 the author goes on to discuss Traube's theory that hydrogen per- 

 oxide plays a part in the process ; concluding that the facts do 

 not support this hypothesis while they are satisfactorily explained 

 by the theory he has offered. — J. (Jhem. Soc, xlix, 94, Feb., 

 1886. G. F. B. 



II. Geology and Natural History. 



1. Gas- Wells on Anticlinals. — Prof. I. C. White,* of the Penn- 

 sylvania Geological Survey, has a paper on "The Geology of 

 Natural Gas," in the Petroleum Age for March, in which, as in 

 a paper in Science of last June, he presents evidence for the 

 conclusion that the underground gas-accumulations of western 

 Pennsylvania exist chiefly along very low anticlinals, and illus- 

 trates the subject with a map, giving the positions of the anticli- 

 nal axes and the gas-wells, from the maps of the Pennsylvania 

 survey and partly his own examinations. The few apparent ex- 

 ceptions among the large wells he refers to the existence of trans- 

 verse anticlinals (whose positions he also indicates on his map), 

 these making an arching in a synclinal at the crossing. The syn- 

 clinals are stated to be regions of subterranean waters and hence 

 of comparatively little free or available gas, where there is any. 

 He" mentions, besides other facts, the case of a well recently 

 located by him on the great Saltsburg axis, north of the town of 

 Grapeville, which, on reaching into the " Murraysville sand " a 

 few weeks ago, yielded an immense flow of dry gas. In contrast, 

 a party from Greensburg put clown a well one mile east of the 

 crest of the same arch or anticlinal, at a locality where the dip had 

 carried the rocks down 250 feet, and got an immense supply of 

 water, and consequently what little gas came up was worthless. 

 Mr. White states the fact from Illinois of recent observation (re- 

 ceived by him from Mr. L. R. Curtiss, of that State) : that along 

 the low anticlinal in Illinois which extends from Ogle County 

 S. 20° E. through Lasalle and Champaign Counties, and thence to 

 Coles and Clark Counties in the southeastern part of the State, 

 " natural gas can be traced in springs and well-borings for a dis- 

 tance of 160 miles ; but it is more prevalent on the crowns of the 

 cross anticlinal axes, as notably the case at Mendota. 



The gas-wells at Erie and Fredonia, N. Y., have been instanced 

 as exceptions to the general rule; but the supply of gas at these 

 places is small, only 20,000 to 60,000 cubic feet daily, according 

 to Professor Orton ; while the great gas-wells deliver daily mil- 

 lions of cubic feet, some in the Murraysville field, it is reported, 

 yielding thirty-three millions per day. " The first Murraysville 

 well has been delivering more than twenty millions of cubic feet 

 of gas daily for nearly ten years ; and, with many other wells in 

 close proximity, the volume has not been appreciably diminished." 

 Moreover, Mr. White says that he finds, on recent examination, a 



* The name J. C. White, on page 228 of this volume, should be I. C. White. 



