426 O. B. HOPKINS STRUCTURAL FEATURES OF PLAIXS OF ALBERTA 



there is no uplift at Mud Buttes, as has heen supposed by many geologists 

 who have visited the area. 



Eegarding Tit Hills, the other center of supposed uplift, the evidence 

 is similar and equally convincing that no local uplift is present. A well 

 was drilled on the north side of these hills, on the supposed uplift, and 

 instead of finding a structural high found the formations at their normal 

 depth. Thus the base of the Colorado found at 154 feet above sealevel 

 at Fabyan, 40 miles to the north, is found here at 233 feet below sealevel, 

 showing the normal southward dip of 914 feet per mile. 



The larger group of hills to the south of Mud Buttes, named Misty 

 Hills, have not been deformed to the same extent as Mud Buttes, but this 

 may be explained readily as due to the greater resistance of their much 

 larger mass. Considerable dislocation of the normal attitude of the strata 

 is found in these hills, however, and this is attributed in part to the 

 movement of the ice-sheet and in part to slumping. 



The nature of the disturbance of the beds at Mud Buttes and Tit Hills 

 is not such as could be attributed to the development of gentle folds. 

 The intensity of the folding and faulting, if due to deep-seated forces, 

 could only have resulted from (a) tremendous local uplift, (b) or from 

 intense lateral compression, such as produces great overthrust faults. 

 We have already seen that there is no intense local uplift present, as no 

 old rocks are brought to the surface. Furthermore, there has been no 

 regional movement that could have produced these local deformations. 

 The region is singularly devoid of structural disturbance; the only fea- 

 ture of note which appears to disturb the generally flat-lying and gently 

 dipping beds is a slight change in strike from southwest to south or 

 slightly east of south. This, however, is a broad regional feature wdiich 

 can best be explained as due to warping of the former Cretaceous basin 

 along broad lines. Such a slight amount of differential movement, neces- 

 sary to produce the observed change in strike of these flat-lying beds, 

 could not be called upon to explain such intense local disturbances as 

 found here. 



Thus the distribution of the formations and the broad consideration 

 of the structure, together with the confirmative evidence from deep 

 borings, lead to the conclusion that the disturbance of the strata is of 

 surficial origin. 



EVIDEXCE OF THRUSTING FORCE 



The similarity of the structure observed in Mud Buttes to that devel- 

 oped in the foothills belt of Alberta, where the limestone ranges of the 



