Maech 6, 1903.] 



SCIENCE. 



387 



magnesium sulphate. With the latter salt 

 the root tip retained its vitality in a normal 

 0.25 solution, hence at a concentration of the 

 pure solution two hundred times as great as 

 the maximum which allowed lupine root tips 

 to survive. Equally interesting results were 

 obtained upon adding calcium sulphate to the 

 solutions. 



It is important, in view of the diverse re- 

 sults obtained, to continue the experiments 

 with many different plants. Until that is 

 done no generalizations are possible, and we 

 may only say that the protoplasm of remotely 

 related plants differs widely in its reaction to 

 pure solutions of various mineral salts; while 

 the addition of a calcium salt would appear 

 to cause a certain amount of uniformity in 

 the effect of each salt upon various organisms. 



Frank Bond discussed ' Irrigation Methods 

 and Machinery,' illustrating his remarks with 

 lantern slides showing how the conditions 

 varied in different states and the different 

 types of dams, reservoirs, canals and devices 

 for measuring the amount of water used. He 

 concluded with some remarks on the great 

 Assouam dam on the upper Nile. 



F. A. Lucas. 



GEOLOGICAL SOCIETT OF WASHINGTON. 



At the 138th meeting of the society, held 

 in the assembly hall of the Cosmos Club, 

 Wednesday evening, February 11, 1903, the 

 following program was presented. 



Mr. W. C. Mendenhall, ' Chitina Copper 

 Deposits, Alaska.' 



The Chitina copper belt is in the eastern 

 part of the Copper River basin, Alaska. 



The deposits which have been exploited here 

 are concentrations in various forms of copper, 

 which is believed to have been distributed 

 originally in minute quantities throughout an 

 extensive series of basalt flows of pre-Permian 

 age. The most promising ore bodies are 

 found near the contact with a heavy lime- 

 stone which overlies the basalts. They occur 

 as veins in the limestone and in the green- 

 stone or as ' bunches ' in the greenstone only. 

 The ores are usually bornite or chalcocite in 

 the surface exposures. Chalcopyrite and na- 

 tive copper also occur. 



Mr. David White, 'An Anthracite Coal 

 Field Three and a half Hours West of Wash- 

 ington.' 



Under this title the speaker contributed 

 some observations on the Sleepy Creek moun- 

 tain basin in Morgan County, West Virginia. 

 It has recently been thought by some geolo- 

 gists that the coal-bearing series here might 

 be of Pottsville age, but the stratigraphic and 

 paleontologic evidence were stated by Mr. 

 White to agree in indicating that the beds 

 belong to the Pocono. 



One very thick, though highly impure, coal 

 has been exposed at a number of localities. 

 Its anthracitic character is ascribed to the 

 porosity of its rock environment and the al- 

 terative influences to which it has been sub- 

 jected because of its extreme eastern position. 

 This position perhaps accounts also for its 

 exceptional thickness. 



Mr. George W. Stose, ' The Structure of a 

 Part of South Mountain, Pennsylvania.' 



South Mountain, the Blue Ridge of southern 

 Pennsylvania, is composed of Lower Cambrian 

 quartzites and shales forming a flat-topped, 

 steep-sided anticline exposing Algonkian vol- 

 canics in the center. The quartzites dip 

 steeply beneath the limestone of the Cumber- 

 land valley and only small local faults, if 

 any, occur along the western flank of the 

 mountain. 



Offsets of the mountain front are due to 

 additional anticlines coming in on the north- 

 west and plunging southwestward beneath the 

 limestone, which partakes of the folding of 

 the mountain rocks. The offset opposite 

 Waynesboro is accentuated by faulting. 



Mr. Geo. Otis Smith, ' Abandoned Stream 

 Gaps in Northern Washington.' 



The cases cited are in the Okanogan valley, 

 and, as shown by photograph and contoured 

 map, are peculiar topographic features, but 

 very common in this region. Such series of 

 gaps on the valley side result from the succes- 

 sive occupation by streams flowing along the 

 side of an expanding valley glacier. Antoine 

 Coulee, near the junction of the Methow and 

 Columbia Rivers has been described by Pro- 

 fessor Russell as the fissure behind a displaced 

 block. Glacial and physiogrraphic evidence 



