256 proceedings: botanical society 



Nevada. The earlier glaciation was much more extensive than the 

 later one, and the ice levels of the two consequently lie several thousand 

 feet apart in altitude on the middle flanks of the range. As the levels 

 are traced upward, however, they are found to converge until in the 

 immediate vicinity of the Sierra crest they cannot be distinguished from 

 each other. Evidently, then, the ice of the two epochs reached prac- 

 tically the same height in the crestal cirques, and the later glaciers 

 started from substantially the same sap line as did the earher ones. Fur- 

 thermore the moraines indicate that the glacierets of recent historic 

 time, many of which were less than one mile long, also started from the 

 sap line left by the Pleistocene glaciers. It is to be inferred, therefore, 

 that at all stages of glaciation the ice filled the crestal cirques to approxi- 

 mately the same depth, and that consequently every glacial episode 

 has reaccentuated the sap line, and has resumed the modeling of the 

 cirques essentially along the lines established by its predecessors. 



Discussion: S. R. Capps said that it was not entirely evident to him 

 why the sap-line should have had the same level at different 'glacial 

 epochs. Matthes replied that he had come to his conclusion on this 

 matter not by analytical reasoning but by following to their converg- 

 ences the trend of the ice-lines or markings on the rocks made at 

 different epochs. Capps favored the idea that the position of the 

 sap-line was due to the height to which snow could accumulate before 

 flow-movement began. Matthes thought this explanation might 

 well be consistent with his idea. 



W. C. Alden said that his experience in glacial studies had been 

 chiefly in regions of sedimentary rocks, and spoke of the phenomena 

 in Glacier National Park. In the development of the fine cirques in 

 thin-bedded sedimentaries there shown he believed plucking had been 

 a very great factor. He had not observed Matthes' sap-line in these 

 cirques. There was good evidence of plucking-efl"ects but not much 

 of abrasion-effects. 



R. H. Chapman said that in his opinion the great variety of profiles 

 in cross-sections of cirques in the Glacier Park regions could be as- 

 cribed to difl"erences in dip of sedimentary beds. 



C. N. Fenner, Secretary. 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 103d regular meeting of the Society was held in the Crystal 

 Dining Room of the New Ebbitt Hotel, at 6.45 p.m., Tuesday, March 

 2, 1915. Eighty-two members and seventy-eight guests were present, 

 this being the regular annual open meeting for the President's address. 



The retiring President, Dr. C. L. Shear, delivered an address on 

 "Mycology in relation to Phytopathology." 



Mr. a. S. Hitchcock addressed the Society concerning the pro- 

 posed publication of a local flora, covering the flowering plants and 

 vascular cryptogams of Washington and vicinity, which is being pre- 

 pared by Washington botanists under the leadership of Mr. Frederick 



