AKTIiaClAL DEKOKMATlOiX OF SOFT BEDS 



831 



of the liea\7 «^iJi'l beds. The experiment just described shows more or 

 less disturbance of the entire thickness of the section. 



Another experimejit of a similar character to tliat already described 

 shows that extensive disturbance and lateral movement mav l)e ])r()diiced 

 in the higjier beds of the experimental section with little or no effxH,-t on 

 the beds immediately below. Shot was used for weightino' the beds shown 

 in figure G, which represents the second experiment. The beds of clay, 

 powdered chalk, and sand were horizontal at the beginning of tbe experi- 

 ment. 0]i one' side of the tank in this experiment thrust-faultino- was 



Figure 7. — Later 8tage in the Defoimation shotvn in Flyuie 



developed in the middle part of the section. In this photograj)!! (figure 

 6) marked bending of the beds and crumpling of the upper beds is shown, 

 with the lower beds entirely undisturbed. The next figure, number 7, 

 shows a later stage of the same experiment. This experiment duplicates 

 one of the conditions characteristic of the'Avon Eiver beds, namely, dis- 

 turbed beds resting on undisturbed beds. _The other essential feature, 

 horizontal beds above the contorted beds, would be supplied by the con- 

 tinuation of the normal processes of deposition laying down horizontal 

 beds after the removal by current scour of the heavier and coarser beds 

 which produced the deformation. 



XXIV — Bull. Geol. Soc. Am., Vol. 28, 1916 



