294 



SCIENCE. 



[N. S. Vol. I. No. 11. 



with all willingness to look on the conti- 

 nents as unstable, it is difficult to believe 

 that they have sufifered changes so great as 

 Spencer announces, not only in the uplift of 

 the AntiUean region, but in the deep de- 

 pression of the axis of Central America, and 

 in the denudation of the (inferred) great 

 banks or continental shelf along the Wind- 

 ward Islands. The strongest proof will be 

 demanded before vertical movements of 

 two miles and a half can be accepted ; and 

 we fear that most readers will take refuge 

 in a verdict of ' not proved.' 



HISTORY OF THE ST. JOHN RIVEE, NEW 

 BRUNSWICK. 



An article on the 'Outlets of the St. John 

 river,' by G. F. Matthew (Bull. Nat. Hist. 

 Soc, New Brunswick, xii., 1894, 43-62), 

 concludes that this river has been built up 

 by contributions from three other systems, 

 whose lower parts are now to be seen in the 

 Eestigouche, Miramichi and Petitcodiac. 

 The evidence of this conclusion is derived 

 from the geological structure of the coun- 

 try, beginning as far back as the Huronian 

 time ; the three rivers whose upper basins 

 now belong to the St. John having been de- 

 fined as basins of deposition in more or less 

 remote geological periods. Thus the St. 

 John river has attained its present magni- 

 tude by the breaking of mountain or hill 

 barriers which once separated its three river 

 systems, and is not a simple valley of con- 

 tinuous growth like the Mississippi (p. 

 55). The difficulty of accepting Dr. Mat- 

 thews' conclusion as the only solution of 

 the history of the St. John does not lie in 

 any objection to the geological history of 

 the region and its several basins of deposi- 

 tion, as far as stated, but in the omission of 

 sufficient consideration of what has hap- 

 pened in the region since it became a land 

 area. It has long been subject to subaerial 

 erosion. During this time it has in all 

 probability been variously warped and 



otherwise moved with respect to its base- 

 level. Its rocks are of diverse resistance, 

 and hence there may have been repeated 

 opportunities for diversion and rearrange- 

 ment of river courses during the long life 

 of the region as a land area. While admit- 

 ting that several geological basins of great 

 antiquity are now drained by a single river, 

 it does not necessarily follow that this river 

 is an immediate descendant of the rivers 

 which at one time or another drained the 

 separate basins. The actual St. John river 

 may once have been larger than now ; its 

 neighbors may have gained drainage area 

 from it instead of losing drainage area to it; 

 but these possibilities are not considered. 



THE ORIGIN OF THE MISSISSIPPI. 



The reference to the Mississippi in the 

 previous paragraph brings up an oft-encouu- 

 tei'ed implication of simple history in the 

 development of this great river, against 

 which there is much evidence. A similar 

 implication is found in a recent State Sur- 

 vey Eeport, where it is stated that, as a re- 

 sult of continental evolution at the close of 

 the Carboniferous period, the drainage of 

 the Ohio region was turned southward 

 "into the great Mississippian bay, which 

 then washed the shores of the new-born 

 continent as far north as the mouth of the 

 Ohio river" ( Geol. Coastal plain of Alabama, 

 1894, 11). It is found again in the ' Story 

 of the Mississippi-Missouri,' where the 

 Mississippi at the close of the Appalachian 

 revolution is described as heading some- 

 where in the Minnesota- Wisconsin region, 

 and flowing southward to its mouth some- 

 where near the present city of St. Louis, 

 whence a deep gulf extended southward to 

 the present Gulf of Mexico (Amer. Geol. 

 iii., 1889, 368). While the southward- 

 flowing streams of the Wisconsin-Minnesota 

 highlands are probably of ancient origin, 

 the southward course of the Mississippi be- 

 tween Tennessee and Arkansas seems to 



