Proceedings Am. Philos. Soc. Vol. LV. 



Plate VI 



7 :'.-'^Mfh 









•f,''.'? 



Figs, i .\xd 2. Two view.s of symmetrical disintegr.a.tion of s.a.nds in 



BEACH TERRACE AT ReHOBETH BeACH, DeL.AWARE. ThE S.ANDS .ARE UNCON- 

 SOLIDATED; THEY OVERLIE THE TaLBOT FORMATION. (PHOTOGRAPH BY AuTHOr) 



