•36 ■ NEW YORK STATE MUSEUM . 



variations from the general direction of dip, and they have also 

 been faulted, producing again local variations, which are most 

 marked near the fault lines. 



The general direction of dip in the immediate district is to 

 the southwest. The amount is variable though seldom exceeding. 

 5°, and the general average is much less than this. The steeper 

 southwest dips are counteracted by occasional changes of dip to 

 the northwest, because of slight folding. The average dip can 

 only be obtained by bringing large distances into consideration. 

 For example, just east of Middleville the summit of the Beekman- 

 town (the most convenient horizon for the purpose) lies at an 

 altitude of 800 feet above sea level. In the deep well at Ilion, 

 approximately 10 miles distant in a direction somewhat to the 

 west of south, the same horizon was reached at a depth of 630 

 feet below the mouth of the well, or 225 feet below sea level, an 

 altitude 1025 feet lower than at Middleville and amounting to a 

 fall of somewhat over 100 feet to the mile. This represents a 

 dip not greatly in excess of 1° in this direction. It is quite pos- 

 sible that this is not along the line of greatest dip, that running 

 somewhat more to the westward, but it is exceedingly unlikely 

 that the general dip exceeds 2°. 



In the near vicinity of faults steep dips have often been pro- 

 duced by the drag of the rock masses on each side of the fault 

 plane as they have moved past one another during the faulting, 

 the layers being bent upward on the downthrow, and downward 

 on the upthrow side of the fault. The less massive and rigid 

 rocks are, the more they yield to this drag, and hence its effects 

 are in general more pronounced on shales. The Utica shales have 

 thus been given very steep dips near the fault lines of the district, 

 being found with inclinations of 50° to 60° and even more. Such 

 steeply dipping shales show magnificently in the east bank of 

 East Canada creek, just below the Dolgeville power house [pl.8]. 

 They are also well shown in some of the small creeks which cross 

 the Little Falls fault line to the east and northeast of Little 

 Falls. 



