MYOLOGY OF THE NORTH CREEK QUADRANGLE 53 



valley of Minerva stream. From North Creek to the map edge 

 the line of the fault is marked by a distinct depression which has 

 befm formed along the belt of weakness. Except near the Hudson 

 river where the weak Grenville is crossed by the fault, a well- 

 'definel fault scarp forms the upthrow side on the west and it is 

 important to note that this scarp strikes at a high angle across the 

 foliat iOn of the rocks, thus proving the independence of the fault 

 and toliation planes. One and one-fourth miles north of North 

 Creek decomposed and somewhat crushed granite marks the passage 

 of :he fault. Just at the map edge the eastern face of the Moxham 

 ' .•>untain mass is a fine illustration of a steep fault scarp rising to 



height of 900 feet. Since the fault here passes through a great 

 mass of rather homogeneous, igneous rock, it is certain that the 

 amount of displacement is not less than looo feet. An interesting 

 feature is the large inclusion of Grenville gneiss just south of 

 Moxham mountain; it occupies such an unusual position because 

 it lies on the upthrow side of the fault in a place fairly well pro- 

 tected from erosion. 



In the stone quarry just east of the main fault and near the 

 map edge, a fault plane with breccia is clearly exposed in both walls 

 of the quarry. Its strike is north 30° east and it appears to be a 

 minor fracture parallel to the larger one. 



At the map edge a fault branches off the main line of fracture 

 and follows the steep mountain side to Fuller pond. Just east of 

 the pond the scarp of Grenville gneiss rises almost vertically for 

 several hundred feet. 



South of the village the North Creek fault is clearly traceable 

 by the steep mountain sides of igneous rock against which the 

 Grenville comes in contact along a straight or at least very regular 

 line as far south as Baker's Mills (Thirteenth Lake sheet). 



Holcombville fault. There is considerable evidence for a fault 

 with a northwest-southeast strike along a nearly straight line pass- 

 ing through the village of Holcombville. It is represented by a 

 broken line on the map because its presence is not regarded as con- 

 clusive. It is thought to extend for some miles into the Thirteenth 

 Lake quadrangle or nearly to the village of North River. The chief 

 evidences for faulting are the long, straight contacts of the Gren- 

 ville against the bases of the high Oven mountain mass of igneous 

 rock and the great mass of syenite within the Thirteenth Lake sheet. 

 No shear zones were noted and the usual steep scarp and the tilted 

 character of the fault block are absent. 



