FOOTHILLS STRUCTURE IN NORTHERN COLORADO 739 



as the result of repeated local arching and contemporaneous 

 erosion, as attempted by former workers in this field. An alter- 

 native interpretation has been advanced by the writer which 



Fig. 15. — Fold en echelon of the Twin Peaks at Boulder. East- west section 



f 



Main T/>n*yr fhv/f -/=?=" 

 At/nor 0/p /ii^/AJ -f.f~ 



7b ///t/sfrafe Cxsts.SY 

 of £v'*ofa/ d/'/D — 

 -fiaci/tz ond their* 

 diGptac«menf:s. 



Fig. 16. — Diagram to illustrate the displacement of the dip faults and their rela- 

 tion to the large thrust faults at Golden. Small diagram shows distortion of inter- 

 fault block due to pressure causing the main fault. The small arrows indicate the 

 direction of displacement of interfault blocks. 



