46 NEW YORK STATE MUSEUM 



has blotched the cliff with iron stain. The summit layers of 

 the Beekmantown are also much more pyritifer'ous than usual. 

 The fault breccia still clings to much of the cliff face, and since 

 the fault plane is nearly vertical, having only the slightest possible 

 inclination westward, it appears much like a vertical dike along 

 the cliff wall. 



About 75 feet thickness of Beekmantown rocks is exposed in 

 the cliff above the creek level, while lower Utica appears at that 

 level on the opposite side of the fault ; hence the throw comprises 

 that thickness of the Beekmantown, the entire Trenton (inclusive 

 of L'owville and Black river), from 40 to 50 feet thick hereabouts, 

 and an unknown amount of the passage beds and lower Utica, of 

 no great thickness however. The throw is therefore in the neigh- 

 borhood of 150 feet, while i mile to the south, where the fault 

 crosses the creek it will not much exceed 25 feet. 



From this point northward to the Dolgeville power plant, at the 

 High falls, a distance of about a mile, the fault runs parallel with 

 the creek and not far distant from it, with steeply updragged 

 Utica shales forming the easterly wall of the gorge. These show 

 beautifully at the power plant [pi. 8 and 9]. A short distance 

 to the east is an old quarry in the Beekmantown at a level 140 

 feet above the creek bed below the fall. Moreover this is n'ot the 

 summit of the BeekmantoAvn though the actual horizon is un- 

 known. More than this thickness of this formation is therefore 

 involved in the fault here, along with the entire Trenton and pas- 

 sage beds, and an unknown, but here considerable amount of the 

 Utica, the throw here being certainly as much as SOO feet and 

 likely more. The increase in throw has therefore been maintained 

 northward, though apparently at a somewhat less rapid rate than 

 at first. 



Beyond this point the creek swerves away from the fault, which 

 becomes wholly lost in heavily drift-filled country. 



One mile above Dolgeville a small fault shows in East Canada 

 creek just at the second big bend beyond the village. The fault 

 is in the Utica shales though the associated thin limestone bands 

 indicate that the horizon is not far above the passage beds. The 



