726 VICTOR ZIEGLER 



assumptions that appear unsound or at least unwarranted to the 

 writer. The chief objections may be summarized as follows: 



1. Objections based on facts : 



i. The steepest dips occur where the formations disappear. 

 For what reason, if their disappearance be due to an unconform- 

 ity? 



2. The greatest amount of overturning (6o° W) is where the 

 greatest thickness of strata is missing. The same question may 

 be asked as for point No. i. 



3. Crumpling is common along the lines of the supposed uncon- 

 formities. 1 Why ? 



4. Crumpling is relatively more severe on the axis of the sup- 

 posed arch, that is, on the line where the greatest thickness of rock 

 is missing. Why ? 



5. Crumpling is relatively more intense at those points where 

 the formations disappear suddenly. Why this coincidence if their 

 disappearance be due to erosion or non-deposition? 



6. There is a remarkable coincidence of an association of 

 maximum divergence of strike lines, steep and overturned dips, 

 maximum crumpling, and the sudden disappearance of a formation. 

 The simultaneous relationship of these to an unconformity is not 

 clear. 



7. There is an absence of shore facies in the sedimentaries. 

 The existence of the Golden arch presupposes the existence of 

 shore conditions, but none of the formations supposedly deposited 

 against this arch show any change in lithological character upon 

 crossing or approaching it. 



8. No similar structures have been recognized elsewhere in the 

 Rockies. 



9. On the bluffs immediately to the south of Clear Creek the 

 Dakota shows a dip of 6o° westward, while less than 100 feet west 

 the Fountain shows a dip of 40 eastward. These dips cannot be 

 explained on the basis of an unconformity. (Not noted by 

 Eldridge.) 



1 See also H. B. Patton, "Faults in the Dakota Formation at Golden, Colorado," 

 Colo. School of Mines Bulletin, III, No. 1 (1905), pp. 26-32. A complete overturn 

 through 180 is here described. 



