612 



SCIENGE. 



[N. S. Vol. VII. No. 174. 



phuricacid and determine the iodine set free by 

 sodium thiosulphate. ' Ttie Relation of Triva- 

 lentto Pentavalent Nitrogen: ' By A. Lachman. 

 Preliminary study of the reactions of nitrosa- 

 mines. ' On Paramethoxyorthosulphobenzoic 

 Acid and some of its Derivatives : ' By P. R. 

 MOALE. ' Decomposition of Paradiazoorthoto- 

 luenesulphonic Acid with Absolute Methyl Al- 

 cohol in the presence of certain substances : ' 

 By P. E. MoALE. The decomposition was 

 studied in the presence of sodium methylate, 

 ethylate, potassium hydrate, ammonia and ani- 

 line. ' Parabenzoyldiphenylsulphone and re- 

 lated compounds : ' By L. C. Newell. ' The 

 Action of Eihylic Oxalate on Camphor : ' By J. 

 B. Tingle. 



J. Elliott Gilpin. 



SOCIETIES AND ACADEMIES. 



geological society of WASHINGTON. 



At the 77th meeting, held in Washington, D. 

 C, on April 13, 1898, Mr. J. A. TaflF, U. 8. 

 Geological Survey, discussed the ' Geology of the 

 McAlister quadrangle.' This quadrangle covers 

 a quarter degree in northwestern Choctaw Na- 

 tion, Indian Territory. Its geology is practi- 

 cally a duplication of the western Arkansas 

 coal field and older Carboniferous rocks. The 

 coal-bearing rocks, shale, sandstone and coal 

 occupy the northwestern half of the quadrangle 

 and are nearly 6,500 feet thick. Two produc- 

 tive coal beds have been developed. One, the 

 Hartshorn or Grady coal, is at the base, and the 

 other, the McAlister coal, is about 1,350 feet 

 higher in the series. Each is about four feet 

 thick and produces a good strong coal. Sand- 

 stone, shale and limestone occur below and 

 south of the coal-bearing rocks and have an ag- 

 gregate thickness of nearly 1,800 feet. The 

 structure is Appalachian. That of the coal 

 field is canoe-shaped synclines and unsymmet- 

 rical anticlines. The rocks south of the coal 

 field are greatly faulted and intensely folded. 

 The faults are overthrust and the folds over- 

 turned toward the north. The displacement of 

 the greater faults are estimated to be from 7,- 

 000 to lOjOOO feet. 



Under title, ' The Probable Age of the McAl- 

 ister Coal Group,' Mr. David White presented a 



synopsis of the results obtained from a study of 

 the fossil plants of theMcAlister,I. T., coalfield. 

 The flora of the Grady or Hartshorn coal he 

 finds to indicate a reference to the ' Lower Coal- 

 bearing Division ' of Winslow, or the basal 

 portion of the Upper Coal Measures of Branner 

 and Smith, in Arkansas, and a stage near the 

 base in the Allegheny Series of the Ohio-Penn- 

 sylvania bituminous regions. The plants of the 

 McAlister coal, about fifteen hundred feet above 

 the Grady coal, assure a correlation with the 

 ' Upper Coal-bearing Division ' of Winslow, in 

 Arkansas, a stage, perhaps near the Lane 

 Shales, in the lower half of the Missourian, in 

 Arkansas, probably below the Pittsburg coal in 

 Pennsylvania, or near coals P or G of the 

 Northern Anthracite field. Vegetable remains, 

 collected by Messrs. TaflF and Richardson from 

 an horizon about two thousand feet above the 

 McAlister coal, constitute a distinctly Coal 

 Measures flora, without any characteristic Per- 

 mian species, and bespeak a remarkable ex- 

 pansion of the Upper Coal Measures, or Mis- 

 sourian, in the Indian Territory coal field, such 

 as is perhaps comparable to the great dialation 

 of the Lower Coal Measures in the Central Ap- 

 palachian region. 



The last paper was by Mr. H. W. Turner on 

 ' The Succession of the Igneous Rocks of the 

 Sierra Nevada.' 



In Jura-trias time in the northern Sierra Ne- ' 

 vada volcanoes poured forth acid lavas, meta- 

 rhyolites and meta-dacites. These acid lavas 

 were followed by more basic lavas, meta-augite- 

 andesites (augite-porphy rites). The succession 

 is here clearly : first, acid; second, intermediate 

 to basic lavas. During nearly all of Cretaceous 

 time, and perhaps also during the Eocene, the 

 volcanic forces of the Sierra Nevada were quies- 

 cent. The first Teritary eruptions of large 

 volume of which there are records were rhyo- 

 lite. After another but shorter period of rest, 

 during which the rhyolitic lavas were partly 

 eroded, the volcanoes emitted vast floods of an- 

 desite. This succession does not accord with 

 the theory proposed by Iddings, that the first 

 eruption of a given volcanic center are of inter- 

 mediate lavas followed by lavas more acid or 

 more basic, or both. 



Wm. F. Morsell. 



