1897.] 



ASHLEY — GEOLOGY OF ARKANSAS. 



295 



throw ; the direction of dip of faults parallel to the strike ; the 

 general character of folding considered over the whole of the dis- 

 turbed region. 



Thus, in the case of overturns, if they are overthrown to the 

 north, the dips being south on both sides of the axis, it is asserted 

 that movement came from the south. In this region, however, we 

 find overturns overthrown both to the north and south. 



a 



Fig. ^^. — Diagram illustrating the effect of horizontal pressure upon a hori- 

 zontal homogeneous bed. 



ir- 



fL 



Figs. 34, 35. — Diagrams showing the eff"ect of original dip upon ultimate 



structure. 



An examination of the subject seems to show that the real deter- 

 mining factor in the direction of overthrow is the initial dip of the 

 strata. Thus a perfectly homogeneous horizontal layer as in Fig. ^^a 



