822 



SCIENCE. 



[N. S. Vol. XXI. No. 543. 



established by the following facts : (1) It 

 possessed even in dilute solution the char- 

 acteristic headache-producing odor; (2) when 

 treated with ferric chloride solution it gave 

 the usual blood-red color, destroyed by dilute 

 hydrochloric acid and not destroyed by dilute 

 mercuric chloride solution; (3) when treated 

 with silver nitrate solution it gave a white 

 precipitate completely soluble in dilute nitric 

 acid. The dried precipitate exploded with 

 violence when thrown upon a hot iron plate 

 or when touched with a glowing platinum 

 wire; (4) analyses of the silver salt showed 

 it to be identical with silver trinitride. 



Further experiments have shown that hydro- 

 nitric acid may be obtained in small quantities 

 by the action upon hydrazine sulphate of cer- 

 tain oxidizing agents other than hydrogen 

 peroxide, some of which have been previously 

 used by other investigators in the quantitative 

 determination of hydrazine. 



At a special meeting of the section held on 

 May 2 at eight p.m., Dr. W. C. Geer, of the 

 department of chemistry, Cornell University, 

 read a very interesting paper entitled : ' The 

 Chemistry of Indium.' 



W. S. Lenk, 

 Secretary. 



THE GEOLOGICAL SOCIETY OF WASHINGTON. 



The 167th meeting was held at the Cosmos 

 Club, April 12. 



The following papers were given as the 

 regular program : 



Terraces of the High Sierra, California: 

 G. K. Gilbert. 



The Sierra Nevada has long been recognized 

 as a broad, sloping plateau having a steep face 

 toward the east and a gentle descent from its 

 crest to the western base. The fact has also 

 been recognized that the general plateau is 

 made up of subsidiary plateaus. In the north- 

 em part of the range it has been shown by 

 Diller and others that various subsidiary 

 plateaus are separated from one another by 

 faults, and their discrepancies in altitude were 

 caused by differential uplift. At the extreme 

 south, in the basin of Kern River, Lawson has 

 ascribed certain subsidiary plateaus to erosion, 



the surface of the range having been partially 

 graded during pauses between epochs of up- 

 lift. The present studies pertain to the higher 

 portions of the range, from the Kern River 

 basin northward to that of the Tuolumne, a 

 distance of more than 100 miles. Within this 

 belt are (1) summit plateaus characterizing 

 interstream areas and recording a long period, 

 or periods, of degradation soon after the com- 

 mencement of the Sierra uplift. Many of the 

 peaks overlooking the summit plateaus, espe- 

 cially in the neighborhood of the crest line, 

 have (2) remnant surfaces of moderate slope, 

 strongly contrasted with the surrounding 

 clitfs, produced for the most part by glacial 

 erosion. And many of the valleys are bor- 

 dered by (3) high terraces, in some cases ex- 

 panded so as to constitute important plateaus. 

 It is believed that the remnants of old topog- 

 raphy at high altitudes were in the main once 

 continuous with the summit plateaus, but the 

 correlation is difficult, because the connecting 

 slopes have been destroyed by the excessive de- 

 velopment of glacial cirques. It is probable 

 also that some of the valley plateaus at high 

 levels will eventually be correlated with sum- 

 mit plateaus farther to the west, and it is also 

 to be anticipated that the plateaus and ter- 

 races of the higher parts of the range will 

 eventually be correlated with similar features 

 near the western base of the rang'e ; but the 

 latter have not yet been studied. In the upper 

 Tuolumne basin a discordance of plateau levels 

 appears to have been produced by compara- 

 tively recent dislocation, and somewhat similar 

 phenomena were observed in the basin of 

 Kings River. 



The plateaus constitute part of the evidence 

 by means of which the history of the uplift 

 is to be read, and they also serve as datum 

 planes from which the amount of subsequent 

 erosion, especially glacial erosion, can be meas- 

 ured. 



The Snowy Range of New South Wales: W. 



LiNDGREN. 



As is well known, the Australian Cordillera 

 follows the eastern coast of the continent un- 

 til, in Victoria, it bends westward and finally 

 dies out. 



