352 



SCIENCE 



[N. S. Vol. XXXrV. No. 872 



"The Isolation of Bacillus Typhosus from But- 

 ter," D. H. Bergey. 



"Note on a Peptid-splitting Enzyme in Wom- 

 an's Milk," Louis M. Warfield. 



"Carcinoma Involving the Entire Kidney" 

 (with two plates), Lindsay S. Milne. 



"A Study of a Case of Thrombo-angitis Oblit- 

 erans, ' ' Harlow Brooks. 



"The Value of the 'Hormone' Theory of the 

 Causation of New Growth," I. Levin and M. J. 

 Sittenfield. 



The contents of the Asirophysical Journal 

 for September are: 



"Spectrum of Comet Morehouse (1908c)," 

 A. de la Baume Pluvinel and F. Baldet. 



"The Discovery of Eclipsing Variable Stars," 

 Joel Stebbins. 



"A New Bright Variable Star, /3 Aurigce," 

 Joel Stebbins. 



"Motion and Condition of Calcium Vapor over 

 Sun-spots and other Special Begions. II.," 

 Charles E. St. John. 



"An Enclosed Arc for Spectroscopic Work," 

 James Barnes. 



' ' The Spectra of Aluminium, Copper and Mag- 

 nesium in the Are under Eeduced Pressure," 

 James Barnes. 



' ' An Inquiry into the Variation of the Spectro- 

 scopic Binary k Pavonis," Alex. W. Eoberts. 



SPECIAL ARTICLES 



THE ORIGIN OF THE GREAT PLAINS 



Passarge's dictum that " Wasser ist nicht 

 im Stande solche Ebene zu erodieren " now 

 seems eminently applicable to vast, arid and 

 remarkably smooth plains other than those of 

 the great South African plateau. In the light 

 of the recent advances in our knowledge of 

 general desert-leveling, or regional planation 

 and lowering without base-leveling, the vast- 

 ness and evenness of the Great Plains lying 

 between the Eocky Mountains and Mississippi 

 Eiver at once raise the query whether genet- 

 ically their dominant characters have been 

 properly interpreted. 



At the present time the geologic formations 

 receiving greatest critical attention are those 

 known as continental deposits, or terranes 

 laid down and preserved on land instead of in 

 lakes or seas. In the recent considerations of 



the subaerial formations so many novelties 

 enter that in many an old and well-known 

 field a new interest is aroused. The Great 

 Plains and their deposits are one of these. 

 On a grand scale they appear to introduce to 

 ns a mode of terranal genesis hitherto almost 

 unrecognized. Continental deposits thus be- 

 gin to assume in this country an importance 

 which has never been before accorded them. 



Singularly enough, the so-called fresh-water 

 Tertiaries of the Great Plains have had as- 

 cribed to them every known method of origin. 

 The same is true of the surface-relief. In the 

 descriptions and discussions of this one geo- 

 logic formation and of this single topographic 

 feature is reflected in all its various phases a 

 century's trend of sedimentative and physio- 

 graphic thought in America. Por this reason, 

 if for no other, the theme is deserving of more 

 than passing notice. 



The origin of the Great Plains and their 

 deposits has been ascribed to (1) normal ma- 

 rine deposition, (2) lacustrine sedimentation 

 in vast bodies and (3) fluviatile aggradation. 

 To these hypotheses must now be added a 

 fourth — that of eolative planation. In the 

 extreme west in front of the Rocky Mountains 

 is a belt of deflative character where often the 

 substructure forms a typical rock-floor. In 

 the broad median belt eolian deposition to 

 vast extent has taken place, and is still going 

 on. In the eastern belt along the Missouri 

 River wind-effects, although extensive, are 

 almost wholly obscured by moist-climate phe- 

 nomena. 



The two essential points to be noted are, 

 first, continental deposits may be as impor- 

 tant as marine or lacustrine deposits; and 

 second, that on the American continent eolic 

 deposits are of vast extent and are being 

 formed under conditions whereby they may be 

 preserved through the geologic ages as ef- 

 fectually as any of the marine Cambrian ter- 

 ranes have been. 



In this new century the theory of eolic 

 planation and deposition promises to be one 

 of the half-dozen great and novel thoughts in 

 the domains of geology. 



Charles E. Keyes 



