314 



\GIENCE. 



[N. S. Vol. XI. No. 269. 



There are three distinct, uncolored tridimen- 

 sional forms. The first is half fan-like in shape, 

 lying almost entirely to the left of the mental 

 point of regard, and includes the numbers from 

 1 to 100. The second includes the names of 

 eight days, from Sunday to Sunday. The third 

 has the names of the twelve months from Jan- 

 uary to December. The paper pointed out the 

 elements which must appear in any theory of 

 the genesis of the phenomena to which this group 



^ ■ Charles H. Judd, 



Secretary. 



CURRENJ NOTES ON PHYSIOGRAPHY. 

 WESTERN NEBRASKA. 



A REPORT on the geology and water resources 

 of the westernmost twelfth of Nebraska, by N. 

 H. Darton (19th Ann. Kept. U. S. Geol. Sur- 

 vey, pt. IV., 1899, 721-785, numerous maps 

 and illustrations), presents a very clear picture 

 of an interesting region. The inter-stream 

 areas are generally plateau-like uplands of Ter- 

 tiary strata, retaining something of their initial 

 smoothness of surface over considerable dis- 

 tances. The sand-hill area of mid-western 

 Nebraska extends west into the broad upland 

 between the North Platte and the Niobrara, 

 where some east-flowing streams are lost. The 

 chief valleys, that of the North Platte being 

 the largest, are cut by streams whose courses 

 seem to be consequent on the general easterly 

 slope given to the region when it was uplifted. 

 Numerous branch streams of unsystematic (in- 

 sequent) arrangement dissect the valley sides, 

 often producing characteristic bad-lands. The 

 insequent dissection has gone so far between 

 North Platte river and Pumpkinseed creek as 

 to reduce an upland to a narrow ridge with nu- 

 merous lateral spurs. Pine ridge, trending 

 east and west near the northern border, is the 

 strongest relief in the State ; it is a cuesta-like up- 

 land whose escarpment is carved into bad-lands 

 by its obsequent streams which descend north- 

 ward to a denuded area of Cretaceous strata 

 that border the southern flank of the Black 

 hills. The present relation of ground water, 

 springs and streams to a structure and form are 

 well set forth in the later pages of the report. 

 The same author contributes a brief account of 

 the Bad Lands of South Dakota and Nebraska 



to the September number of the National 

 Geographic Magazine. 



Mention may be made in this connection of 

 an article by W. D. Matthew on the interpre- 

 tation of the White river Tertiary strata of 

 Nebraska and South Dakota as an seolian in- 

 stead of as a lacustrine formation {Amer. Nat., 

 xxxiii., 1899, 403-408). 



THE MISSISSIPPI AND MISSOURI RIVERS. 



The annual reports of the commissions on 

 our two greatest rivers (Apps. WW and XX., 

 chief of engineers. United States Army, Wash- 

 ington, 1899) contain a large amount of interest- 

 ing matter, whose discovery would be much 

 facilitated if the reports were edited with more 

 consideration for their readers. Hundreds of 

 pages without adequate tables of contents and 

 with unchanged page headings make the use of 

 the reports difficult. Numerous measured sec- 

 tions of the Mississippi lead to the conclusion 

 that if the banks are properly revetted to pre- 

 vent erosion, while leveeson the adjacent flood- 

 plain restrain the spread of high waters, the 

 channel will be deepened and its capacity to 

 discharge floods increased. The Yazoo basin 

 has 310 miles of levees to protect 7100 square 

 miles of surface. Much money has been spent 

 on the levees by local authorities, and yet it is 

 estimated that the volume of the levees must 

 be increased by more than half in order to 

 bring them up to the proper size. $20,000,000 

 will be needed to complete the entire levee 

 system ; over $2,000,000 having been spent in 

 1899. The heights of floods, their progress 

 down the river, the locations of levees and 

 areas of overflow are shown on various plates 

 and maps. Besides a new edition of the famous 

 eight-sheet map of the lower Mississippi, a 

 four-sheet map of the upper part of the river 

 was issued during the past year on a scale of 

 1 : 316,800. No relief is indicated except along 

 the borders of the floodplain, but this suffices 

 to suggest that the valley is the work of a 

 larger river than that now flowing in it ; not 

 merely because the valley is wider than the 

 river, but because the curvature of the valley 

 is of a larger pattern than the present river 

 seems capable of producing. The narrow post- 

 glacial rock-walled channel just above Keokuk 



