504 



NATURE 



[September 24, 1891 



one Rhomb-amarked Snake {Psammophis rhombeatus), four 

 Crossed Snakes {Psammophis crucifer), one Hygian Snake 



{Elaps hygia), two Snakes {Dasypeltis scabra) from South 



Africa, presented by Messrs. Herbert Melville and Claude 

 Beddington ; one Smooth Snake {Coroiiellalcvvis), two Common 

 Snakes {Tropidonotus natrix) from Oxfordshire, presented by 

 Mr. A. W. S. Fisher ; one Otter {Lutra vulgaris) from South 

 Wales, received in exchange ; two White-tailed Sea Eagles 

 {Halia'etus albicillays) from Norway, three Indian Python 

 {Python molurus) from India, deposited ; one Macaque Monkey 

 {Macacus cynomolgus) ixom India, one Pardine Genet (Geneda 

 pardina) from West Africa, purchased ; one Vinaceous Turtle 

 Dove ( Turtur vinaceus), bred in the Menagerie. 



OUR ASTRONOMICAL COLUMN. 



Lightning Spectra. — Mr, W. E. Wood, of Washington, 

 has continued his observations of lightning spectra for the pur- 

 pose of determining the origin of some of the lines previously 

 recorded by him (Nature, vol. xlii. p. 377). The result is that 

 he is now able to say, in the Sidereal Messenger for August : — 

 "Lightning spectra present but the characteristic lines of 

 oxygen, hydrogen, nitrogen, and carbonic acid, and — what was 

 puzzling to me— the line of the vapour of sodium. The absorp- 

 tion bands which I find in lightning spectra I think might be 

 produced by the moisture in the air, a large quantity being 

 present during thunderstorms." It is suggested that the sodium 

 line owes its presence to the existence of meteoritic debris in the 

 atmosphere. 



A New Asteroid. — The 315th asteroid was discovered by 

 Charlois on September i. 



THE INTERNATIONAL GEOLOGICAL CON- 

 GRESS : WASHINGTON MEETING. 



T^HE fifth meeting of the International Geological Congress, 

 •*■ being the first ever held in America, was held at the 

 Columbian University, Washington, from August 26 to Septem- 

 ber I, with an attendance of sixty or seventy foreigners, from 

 Austria-Hungary, Canada, Chili, France, Germany, Great 

 Britain, Mexico, Peru, Roumania, Russia, Sweden, and Switzer- 

 land, and about two hundred members from the United States. 

 The papers and discussions were generally in English, though 

 French and German were to some extent spoken. French has 

 been the language of all the previous Congresses. 



Profs. James Hall and James D. Dana were elected Honorary 

 Presidents, and J. S. Newbery Acting President. Owing to the 

 absence of the latter, the chair was filled in turn by several of 

 the Vice-Presidents. 



First Day. — After the election of officers, as nominated by 

 the bureau, Prof. Joseph Le Conte, as senior Vice-President, 

 took the chair, and delivered the opening address, in which he 

 said that the idea of an International Congress was born in 

 America in 1876. Previous meetings have been held at Paris in 

 1878, Bologna in 1881, Berlin in 1885, and London in 1888. 

 He briefly stated the purposes of this Congress, which were 

 afterwards carried out — namely, to discuss classification of the 

 Pleistocene rocks, of correlation, and of map notation. He 

 compared the maps of Europe and America, showing the com- 

 plexity of the former and the simplicity of the latter. He then 

 considered some points in American geology : — (i) The 

 general continuity of the record. (2) The prevalence of ex- 

 tensive faults, ranging from 100 to 2000 feet, and extending 

 over great distances, (3) Peculiarities of mountain structure. 

 Prof. Gilbert has discovered a new type of mountains formed by 

 uptilted strata. The Sierra Nevada is an illustration. (4) Ex- 

 tensive lava floods, covering areas from 10,000 to 100,000 square 

 miles in extent, and from 2000 to 4000 feet deep. No such 

 floods are found elsewhere. Those of India are the nearest 

 approximation ; but in Europe the lava beds are small and much 

 cut up. (5) The great continental movement, commencing in the 

 later Tertiary, and terminating in the beginning of the Quaternary, 

 which has caused changes of level amounting to 2500 or 3000 



NO. II 43, VOL. 44] 



feet on both sides of the continent. (6) The ice-sheet of the glacial 

 epoch was first and most completely demonstrated in America. 



Other addresses were delivered by Mr. Hubbard, Chairman of 

 the Local Committee ; Mr. Noble, Secretary of the Interior, who 

 has official control and supervision of the Geological Survey of 

 the United States ; Prof. Hughes of England, Prof. Gaudry of 

 France, and Major Powell, Chief of the Geological Survey. 



Second Day. — The entire day was occupied by a discussion 

 on classification of the glacial Pleistocene deposits. Prof. T. C. 

 Chamberlin opened the discussion by stating that classification 

 might be made on three grounds: (i) structural; (2) chrono- 

 logical ; (3) genetic. The first was very easy, being an obvious 

 division into assorted and unassorted drift. The second was 

 extremely difficult, and could not be accurately made till after a 

 full determination of the third. He accordingly proposed the 

 following general classes: (i) formations produced by the 

 direct action of Pleistocene glaciers ; (2) formations produced by 

 the combined action of Pleistocene glaciers and accompanying 

 glacial drainage ; (3) formations produced by glacial waters 

 after their issuance from Pleistocene glaciers ; (4) formations 

 produced by floating ice derived from Pleistocene glaciers ; (5) 

 formations produced by shore ice and ice floes due to low 

 Pleistocene temperature, but independent of glacier action ; (6) 

 formations produced by winds acting on Pleistocene glacial and 

 glacio-fluvial deposits under the peculiar conditions of glaciation. 



This paper was discussed very thoroughly. Prof. T. McK. 

 Hughes pointed out that the classification suggested by Prof. 

 Chamberlin was purely genetic. He then explained the abun- 

 dance of striated boulders in one part of the glacial deposits 

 and their absence in another. If the supply of material (that 

 is, of rock bosses above the ice) ceases at any point, then all the 

 boulders will gradually sink through the ice and become glacial ed 

 at the bottom. Prof. Hughes also thought that two distinct 

 types of ridges formed of glacial material were confused under 

 the names — kames, osars, and eskar. He also explained the 

 "pitted plains" as due to an unusual interruption between the 

 hills or ridges of eskar character. He expressed his opinion 

 that the glacial period was a continuous one, in England at 

 least, except for slight changes due to unimportant oscillations. 



Mr, McGee mentioned the importance of land forms in inter- 

 preting geological processes. Any primary geological classifica- 

 tion must be genetic. He discussed in detail the following 

 scheme of classification of Pleistocene deposits : — 



Classification of Pleistocene Formations and Land Forms. 



A. Aqueous : 



1. Below base level, 



a. Marine. 



b. Estuarine. 



c. Lacustral. 



2. At base level. 



a. Littoral. 



h. Marsh. 



c. Alluvial (certain terraces, &c.). 



3. Above base level. 



a. Torrential. 



b. Talus (including playas). 



B. Glacial : 



1. Direct (Chamberlin's Class I.). 



2. Indirect (Chamberlin's Classes II. to V., in part), 



C. Aqueo-Glacial (Chamberlin's Classes II, to V,, in part). 



D. Folic (Chamberlin's Class (?) VL), 



E. Volcanic : 



1. Direct. 



a. Lava sheets. 



b. Cinder cones. 



c. Tuffs, lapilli sheets, &c. 



2, Indirect. 



a. Ash beds. 



b. Lapilli sheets. 



Prof. Chamberlin, in closing the discussion, said that there 

 was great difficulty in applying a chronological classification, 

 and that such a classification might even act as a barrier to 

 observation and to the recognition of the truth. Chronological 

 classification is the ultimate goal of glacial studies, but it is 

 something for which we are not as yet prepared. Red, oxidized 

 sub-soils are not developed in northern latitudes. Organic 

 deposits between glacial layers are abundant in the West, but 

 do not belong to a single horizon. Many facts of erosion and 



