lLolian Action in Southern New England. 65 



"It was so far as I know on the 5th of April, 1876, that G. 

 Berendt for the first time called the attention of North German 

 geologists to peculiar facets which are seen on pebbles in the 

 glacial drift. Since this time, these so-called ' drei-kanter, or 

 ' Kantengerolle ' have interested geologists, and a great deal has 

 been written on this subject. They were regarded as the work 

 of ice, of great pressure, etc., until Mickwitz in his treatise gave 

 the right key to the puzzle, in that he proved that these facets 

 are merely a phenomenon of smoothing by sand (Sandschliffer- 

 scheinung), a view which since then has merely been confirmed 

 by Credner, Heim, Saner, and others. Views at present differ 

 only concerning the manner in which these planes were cut. I have 

 collected a number of such edged pebbles in different parts of 

 the desert : first I found them in Wady Araba in the Arabian 

 desert, then between Giseh and Abu Roasch on the border of the 

 Libyan desert; and Dr. Sarasin has found them in the Sinai 

 peninsula. 



"According to my observations," continues Walther, "it is 

 limestone of the Cretaceous formation, of fine, compact, very 

 uniform grain, which in Egypt forms dreikanter. I have not 

 found other varieties of rock in this form. The Eocene lime- 

 stones may be too soft, the Nummulitic rock too unequally hard, 

 and the crystalline rocks, as I have to show in the following 

 pages, so quickly decompose in the desert that they are not 

 adapted for forming dreikanter. 



"The number of corners ground on varies as much as does the 

 size of the pebbles, and neither are causally connected. I found 

 einkanter (pebbles with one edge or arris) a foot in diameter 

 (fussgrosse) and nut-sized stones with five edges (ftinfkanter) and 

 conversely. 



"The edges are of unequal sharpness, and I believe I have ob- 

 served that the edges are merely due to the fact that two ground 

 flat surfaces intersect each other so that the expression ' facetted 

 pebbles' (Facettengerolle) appears to me to be more correct 

 than edged-pebbles (Kantengerolle). 



" A connection between the direction of the edges and the 

 direction of the wind could not be found, and this seems to me 

 easily understood since I did not observe constant winds, and 



Johannes Walther: Kantengerollen in cler Galalawuste ; Berichte der math, 

 phys. Klasse der Sachs. Gesell. der "Wissenschaft, Nov. 14, 1887; B. G-einitz : 

 Ueber Kantengerollen; Neues. Jahrb. fur Min. Geol. and Pal. Stuttgart, 1887 

 (II), p. 78. Heim: Kantengeschiebe aus dem norddeutschen Diluvium ; Yiertel- 

 jahrsch r. d. Furcher. Natur. Gesellsch., 1888. F. Wahnschaffe, Beitrag. zur 

 Lbssfrage; Jahrbuch d. Konig- Preuss. Geol. Landesanstalt, Berlin, 1890, pp. 

 328-346. A. Sauer und C. Chelim : Die Ersten Kantengeschiebe im Gebiete der 

 Bheinebene; Neues Jahrb. f. Min., etc., 1890, ii. A. Sauer: Ueber due seolische 

 Enstehung des Loss am Rande der norddeutschen Tiefebene ; Zeitschr. fur Natur- 

 wissenschaften, Bd. Ixii, Halle, 1889; Neues. Jahrb. f. Min., 1888, Bd. ii, s. 

 300-304. Dames und Wahnschaffe: Zeitschrift d. Deutsch. Geol. Ges., 1887, s. 

 226-227 und 229. A. Geikie in the 3d edition of his text-book refers to other 

 papers. 



Am. Jour. Sci.— Third Series, Yol. XLVII, No. 277.— Jan., 1894. 

 5 



