668 



SCIENCE. 



[N. S. Vol. XVII. No. 434. 



of the flora and fauna of the region; and 

 Paul Bartsch presented some ' Notes of the 

 Herons of the District of Columbia.' He 

 described at some length a colony of night 

 herons, showing various views of the nests 

 with eggs and young in various stages, and 

 also exhibited some pictures of young blue 

 herons and of the great white egret, expressing 

 his regret that these birds had subsequently 

 been nearly all killed by hunters. 



F. A. Lucas. 



GEOLOGICAL SOCIETY OF WASHINGTON. 



At the 140th meeting of the society, held 

 in the assembly hall of the Cosmos Club, 

 Wednesday eve'ning, March 11, 1903, the fol- 

 lowing program was presented: 



Mr. A. J. Collier, ' Coal-bearing Series of 

 the Yukon.' 



About 9,000 tons of coal have been mined 

 along the Yukon since 1897. Above the Tan- 

 ana the coal occurs in small Eocene basins 

 surrounded by older rocks. Below the Tan- 

 ana a coal-bearing formation, called' the Nu- 

 lato sandstone, is exposed almost continuously 

 for 400 miles. From the lowest beds of this 

 series cycads of Jurassic and Lower Creta- 

 ceous aspect were obtained in the same matrix 

 with dicotyledons of Upper Cretaceous aspect. 

 In other places Tipper Cretaceous plants and 

 invertebrates and Eocene plants were obtained, 

 but the horizons could not be differentiated 

 stratigraphically or lithologically, and con- 

 tinuous sedimentation from the Middle Cre- 

 taceous to the Upper Eocene is suggested. 

 The Nation Eiver coal bed on the upper Yu- 

 kon may be either Permian or Eocene over- 

 thrust by Permian limestones. 



Mr. Prank C. Calkins, ' Soils of the Wheat 

 Lands of Washington.' 



The soil covering the higher portions of the 

 Columbia plains has generally been considered 

 to be residuary, and derived from the under- 

 lying Miocene basalt. Recent observations, 

 however, have led the author to believe that 

 this soil is an eolian deposit. The argument 

 for the eolian hypothesis is based on the phys- 

 ical and chemical properties of the soil and 

 the complete lack of transition between it 

 and the underlying rock. The wind-blown 



material is supposed to come from the soft 

 volcanic sediments that overlie the basalt in 

 the southern portion of the Columbia plains. 



Dr. H. S. Washington, ' The Calculation 

 of Center-points in the Quantitative Classi- 

 fication of Igneous Rocks.' 



After briefly explaining the main features 

 of the new classification (see Science, Feb- 

 ruary 27, 1903, pp. 341 et seq.), the speaker 

 showed that, as the classification is strictly 

 quantitative, the theoretical chemical and 

 normative composition of the center-point of 

 any given classificatory division could be cal- 

 culated mathematically. This is accomplished 

 by forming equations expressing the defini; 

 tion of the center-point of each successive 

 classificatory division, from the solution of 

 which the norm is obtained. Prom this the 

 chemical composition follows. The method 

 will be explained at length in a publication 

 which is soon to appear. 



The result of a calculation of the average 

 igneous rock, based on nearly 2,000 reliable 

 analyses, taken from a collection which has 

 been made by the speaker, was also communi- 

 cated. It was shown that this latest estimate 

 approximates very closely to those of Clarke 

 and Harker. 



Professor Edward Mathews, ' The Practical 

 Working of the Quantitative Classification.' 



The author presented the salient features 

 of the new classification as indicated by the 

 averaging of some 500 analyses according to 

 subrangs, rangs, orders and classes. The 

 figures seem to indicate that the new rules 

 are applicable with little or no subjectivity, 

 but that little can be told with certainty re- 

 garding the classificatory position from an 

 inspection of the chemical analysis. 



The author commended the simplicity of 

 the basal conceptions and the resulting sim- 

 plicity of definitions; the suggestion of new 

 lines of investigation developed by the classi- 

 fication; and the mnemonic features of the 

 nomenclatures. He, however, criticized the 

 choice of order names and roots, the subor- 

 dination of texture, the fact that the litera- 

 ture would be deprived of its usefulness and 

 the extreme emphasis likely to be placed on 

 chemical analyses of single specimens. 



