EDITORIALS. 847 



theoretical evolution applicable only to the land of man's origin. 

 The present stage of civilization is certainly not an immediate 

 derivative of the next preceding, but has been imposed- upon it 

 unconformably, so to speak, and disjunctively.- It is intrusive or 

 superposed, and not derivative. So it is probable that the pecu- 

 liar phases of the higher civilizations found in Central and South 

 America were intrusive and not derivative. It is, therefore, not 

 improbable that the entire succession of civilizations on the 

 American continent consists of a series of intrusions or super- 

 positions from the west and from the east, overlapping each 

 other unconformably and disjunctively. They can, therefore, be 

 worked out safely upon no theory of genetic succession. Each 

 factor must be determined by means of its own inherent evi- 

 dence. T. C. C. 



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Professor James D. Dana has a short article in the Novem- 

 ber number of the American Journal of Scie?ice z touching upon 

 the recent discussion of the divisibility of the glacial period, in 

 which he draws forth generalizations on two important lines, viz., 

 (i) the personal attitude of writers on the subject, and (2) the 

 difference between the glacial phenomena of New England and 

 of the upper Mississippi basin. These seem to us to lie in the 

 right direction, in the main, but in both cases to have somewhat 

 missed the truest lines of distinction and to have fallen short of 

 the most significant features. Professor Dana draws attention to 

 the divergent views of New England and of western glacialists, 

 and concludes that there must be some difference in the phe- 

 nomena of the two regions to account for the differences of view. 

 This seems to us very true and very important. The difference 

 in the phenomena is, however, we think much more radical, and, at 

 the same time, much more simple than that suggested by Pro- 

 fessor Dana. It is, to our view, simply this : In New England 

 only the latest epoch of the glacial period is distinctly repre- 



1 New England and the Upper Mississippi Basin in the Glacial Period. Am. Jour, 

 Sci. III., Vol. XLVI., No. 275, Nov., 1893, pp. 327-330. 



