430 



SCIENCE. 



[N. S. Vol. XI. No. 272. 



Survey, stated that a fluviatile origin for the 

 tertiary beds of the west was not considered, 

 because their lacustrine nature was indicated 

 by physiographic evidence. 



Mr. Whitman Cross cited Blanford's descrip- 

 tion, published in 1879, of the Gondw^na beds 

 in India, and pointed out that the conclusion, 

 then announced, as to the probable origin of 

 these and other beds in India had pi'obably been 

 overlooked by geologists quite generally. The 

 same criteria applied to the tertiary and 

 mesozoic beds of the Rocky Mountain region 

 would lead to the conclusion that many of 

 them were of fluviatile origin. Mr. Cross, how- 

 ever, questioned the value of the criteria em- 

 ployed by Blanford, Penck and Davis, and 

 would give most weight at present to the ex- 

 tent and distribution of the formations in 

 question, and their relation to continental 

 areas. 



Mr. Bailey Willis remarked that he had been 

 in the habit of reasoning back from conglom- 

 erates in order to reconstruct former physio- 

 graphic conditions. Thus the conglomerate of 

 the Puget Sound Basin, covering perhaps 10,- 

 000 square miles, was formed by glacial streams 

 in Pleistocene time. The Pliocene conglom- 

 erates of California are delta deposits and are 

 associated with uplift. The Eocene conglom- 

 erate of Washington State was laid down at the 

 foot of steep bluflfs of granite. The Pottsville 

 conglomerate, composed almost wholly of re- 

 sidual quartz and widely distributed, can have 

 been derived only from a coastal plain where 

 it had been concentrated by marine action, and 

 thence distributed by marine or fluviatile cur- 

 rents. 



Mr. G. F. Becker pointed out that a lake]was 

 often only an expanded river and suggested 

 that a more useful distinction than that between 

 lacustrine and fluviatile deposits, would be one 

 between materials laid down in rapidly moving 

 and in comparatively still water. Deposits laid 

 down by streams have their particles imbricated 

 in one dominant direction. Beach deposits are 

 capriciously imbricated and their pebbles are 

 asymmetric. 



F. L. Eansome, 

 David White, 



Secretaries. 



BIOLOGICAL SOCIETY OF WASHINGTON. 



The 319th meeting was held on Saturday 

 evening, February 24th. W. A. Orton spoke 

 of 'The Sap Flow of the Maple in Spring,' de- 

 scribing a series of experiments undertaken 

 with a "view of ascertaining the cause of the 

 the phenomenon. The results showed that it was 

 due to plant physics rather than plant physi- 

 ology, and had a direct relation to temperature, 

 the sap being expelled by the expansion, caused 

 by warmth, of the gas contained in the wood 

 cells. M. B. Waite described ' The Peach 

 Orchards of Michigan,' stating that they were 

 located on the eastern shore of Lake Michigan, 

 this body of water having the effect of mitigat- 

 ing the temperature of the region. Most of the 

 farms, the speaker stated, were comparatively 

 small, running from fifty to eighty acres in 

 size, but owing to the methods of cultivation 

 they yielded a good profit. Various methods 

 of cultivation were discussed and the speaker 

 touched briefly upon the disease of the peach 

 known as 'little peach.' Both papers were 

 illustrated by lantern slides. 



F. A. Lucas. 



DISCUSSION AND COBBESPONDENCE. 



INFINITESIMALS. 



To THE Editor of Science : Will you kindly 

 accord me space for a few remarks about Infinity 

 and Continuity which I seem called upon to 

 make by several notes to Professor Royce's 

 Supplementary Essay in his strong work ' The 

 World and the Individual '? I must confess that 

 I am hardly prepared to discuss the subject as I 

 ought to be, since I have never had an oppor- 

 tunity sufficiently to examine the two small 

 books by Dedekind, nor two memoirs by Can- 

 tor, that have appeared since those contained 

 in the second volume of the Acta Maihematica. 

 I cannot even refer to Schroder's Logic. 



1. There has been some question whether 

 Dedekind' s definition of an infinite collection 

 or that which results from negativing my 

 definition of a finite collection is the best. It 

 seems to me that two definitions of the same 

 conception, not subject to any conditions, as a 

 figure in space, for example, is subject to geo- 

 metrical conditions, must be substantially the 



