August 5, 1910] 



SCIENCE 



187 



seven miles and is faintly traceable for about twice 

 this distance. Another train, not previously de- 

 scribed, but composed of bowlders of the same 

 rock and probably derived from the same source, 

 extends about sixteen miles directly south from 

 Frye's Hill. This train is not so well defined, it is 

 more diffuse and has not yet been traced through 

 the whole distance. Although apparently the 

 same rock, these bowlders are all well rounded and 

 show more weathering than the angular blocks. 

 The relations and apparent significance of these 

 separate trains were briefiy discussed. 

 Shorelines of the Glacial Lakes in the Oherlin 

 Quadrangle, Ohio: Frakk CABiSTEY, Granville, 

 Ohio. 



The paper described the varying features shown 

 in the shorelines of the Maumee, Whittlesey and 

 Warren lake stages, and discussed the factors in- 

 volved. 



Isohases of the Algonquin and Iroquois Beaches 

 and Their Significance: James Walter Gold- 

 THWAiT, Hanover, N. H. (Introduced by F. B. 

 Taylor. ) 



During the past five years, instrumental meas- 

 urements of altitude of the raised beaches of Lake 

 Algonquin in Illinois, Michigan, Wisconsin and 

 the province of Ontario, have provided new data 

 for the construction of isobases of elevation of the 

 Algonquin beach in an area 450 miles east and 

 west by 300 miles north and south. These meas- 

 urements not only fix the identity of the Algon- 

 quin beach throughout that region, but disclose 

 the exact direction and rate of post-Algonquin 

 tilting at all places within it. It is possible, 

 moreover, to fix the position of an " isobase for 

 zero," or "hinge line," northeast of which there 

 has been differential uplift, but southwest of 

 which no uplift since the making of the Algonquin 

 beach. This horizontal portion of the water-plane 

 is believed to indicate the original height of Lake 

 Algonquin and seri'es as a datum plane from 

 which to ebmpute the amount of uplift of more 

 northerly localities. On the basis of measure- 

 ments by Spencer, Gilbert, Coleman and Fairchild 

 on the Iroquois beach, isobases are drawn for that 

 plane over Lake Ontario. The Iroquois and 

 Algonquin planes are then compared. These con- 

 clusions are reached: (a) that these two stages 

 of the neighboring lakes were nearly contem- 

 poraneous, but that the Iroquois is probably 

 somewhat older; (6) that the diflterential uplifts 

 in which the Algonquin-Iroquois region partici- 

 pated, although of well-nigh continental extent, 

 were here (as in the ease of Lake Agassiz) of 



wonderful regularity, and (c) that whether due 

 to isostacy or not, the uplifts centered in the 

 Laurentian oldland, and the isobases bear a sig- 

 nificant relation to its border, as DeGteer pointed 

 out nineteen years ago. 



The paper was discussed by J. W. Spencer, 

 Frank Carney and F. B. Taylor, with reply by the 

 author. 



The Diversion of the Montreal River: Robeet 

 Bell, Ottawa, Canada. 



This paper described a remarkable example of 

 change in the destination of a large river in which 

 the stream has been diverted in post-glacial times 

 into a new channel that carries its waters all the 

 way to its present mouth in a straight course of 

 90 miles, which lacks only 45° of being exactly 

 opposite to that of the upper part of the stream, 

 as well as its former continuation below the point 

 at which the change took place; that is to say, 

 that at a certain point the course of the river was 

 turned round through an angle of not less than 

 135°, or from a north to a southeast direction, 

 and made finally to discharge into the Atlantic 

 Ocean instead of Hudson Bay. This singular oc- 

 currence was rendered possible from the fact that 

 in one part of its course the river was barely able 

 to pass across what has now become a low divide, 

 and that a slow rising or tilting of the land to 

 the southward gradually stopped the northward 

 flow of the river, while at the same time the 

 changing conditions induced a process of " stream- 

 robbing " through a dam of loose drift material 

 a short distance east of this increasing obstruc- 

 tion. The paper described numerous facts, which, 

 taken together, seem to prove the manner in 

 which this important and interesting phenomenon 

 was accomplished. 



On the Relative Worh of the Two Falls of 'Niag- 

 ara: J. W. Spencee, Washington, D. C. 

 This paper should be considered as an addi- 

 tional chapter to " The Evolution of the Falls of 

 Niagara," by the writer, wherein the work of the 

 smaller cataract and the relative efficiency were 

 scarcely considered. The American ialls carry 

 only five per cent, of the total discharge, and are 

 now some 50 feet lower than formerly, with the 

 recession, as affected by the talus, undeterminable 

 by measurement, but calculated at 0.27 foot a 

 year, as probable. The removal of the fallen 

 masses of limestone beneath the main cataract, 

 below a depth of 72 feet, appears to be largely by 

 solution. By soundings, experiment and calcula- 

 tion it is found that approximately a third of the 

 periodic law, on an increasing helix, on a half 



