May 3, 1895.] 



SCIENCE. 



487 



its bureau to take in regiird to this subject 

 the measures that appear necessary. In 

 particular, it leaves to each of its mem- 

 bei-s entire freedom, considering alone as 

 essential that the Society, on this important 

 occasion, may be assured of having tlie 

 place due it." 



Professor Yasiliev expects that the inau- 

 guration of the Lobachevskj' monument at 

 Kasan will take place in August or Sep- 

 tember, 1896, and counts on having there 

 a large number of eminent mathematicians, 

 and will profit by the occasion to propose 

 definitely the organization of the Interna- 

 tional Congress, and then official calls will 

 be issued to meet for the purpose of final 

 organization in 1S97 at a city of Belgium or 

 Switzerland. 



George Bkuce Halsted. 

 Austin, Texas. 



CURRENT XOTES 02f PHYSIOGRAPHY (V.). 

 THE EXTINCT LAKE PASSAIC. 



The annual report of the Geological Sur- 

 vey of New Jersej- for 1893 contains a long 

 report on surface geologj-, in which there 

 is an interesting chapter on Lake Passaic, 

 an extinct glacial lake, by R. D. Salisburj' 

 and H. B. Kiimmel. First mentioned by 

 Professor Cook in his annual report for 1880, 

 Lake Passaic is now carefully traced by its 

 Bhore lines and the deltas built in it by 

 streams. Its basin was limited on the west 

 by the slope of the crystalline highlands ; 

 on the south and east by one of the curved 

 trap ridges of the Watchung or Orange 

 mountains ; while on the north it was en- 

 closed by ice. Most remarkable of all the 

 shore deposits in the lake waters is the great 

 morainic embankment that was built across 

 the basin from Morristown to Madison dur- 

 ing the furthest advance of the ice sheet 

 into the lake waters ; the lobate front of this 

 bank standing up with great distinctness 

 north of a marshy plain, which now rep- 

 resents part of the lake bottom. 



The outlet of the lake was, for a time at 

 least, by a notch in the trap ridge near its 

 southern end, at a height of 331 feet above 

 sea level. Twenty-five miles to the north, 

 the records of the lake level now stand 

 sixtj--seven feet above the lowest shore line 

 at the southern end of the basin. Many 

 details of iutei-est are considered in the re- 

 port ; none more surprising than the depth 

 of the drift-filling in the notch of one of the 

 trap ridges at Summit (where the Morris and 

 Essex Eailroad crosses the ridge), from 

 which a preglacial discharge of the inner 

 vallej' at this point is fairly inferred. An 

 excellent map accompanies the report. 



LOCAL DISPLACEMEXT OF THE MISSISSIPPI. 



The annual report of the Iowa geologi- 

 cal survey for 1893, just issued, contains a 

 chapter bj' C. H. Gordon on a former channel 

 of the Mississippi, now filled with drift. 

 The modern river has cut a narrow rock- 

 bound gorge, five miles to the east of the 

 former valley, and about ten miles long ; its 

 lower end being at Keokuk, where the Des 

 Moines river comes in fi-om the west. A 

 general study of the surface and the records 

 of a deep well indicate that the earlier 

 valley was about three times as broad and 

 twice as deep as the new gorge. The gorge 

 being hardly more than in its 3-outh, the 

 earlier vallej- was certainly not advanced 

 beyond its early adolescence. It therefore 

 clearly indicates that during only a com- 

 paratively short preglacial time did the 

 region stand as high as or a little higher 

 than now ; most of its preglacial history 

 must have been pa,ssed at a less elevation 

 above baselevel. To speak of the pre- 

 glacial channel as a ' measure of vast de- 

 nudation ' (p. 250) therefore seems some- 

 what inappropriate ; it was onlj' the begin- 

 ning of a denudation that could in a geo- 

 graphical sense be called vast. The vast 

 denudation is more really shown in the 

 stripping of an unknown thickness of strata 



