24:2 E. T. Long— Minor Faulting 



angles up to those very nearly vertical. One good exam- 

 ple of the horizontal type is shown at the water level of 

 the pool at the foot of the big Falls at Ludlowville, north 

 of the village, and just below the dam. ( See fi.g. 8. ) The 

 displacement is probably six inches. As the pool does 

 not dry np even in time of drought and no boat is pro- 

 vided for the convenience of visitors it was impossible to 

 get nearer the fault than a hundred feet or so. It is about 

 35' below the Tully, the movement offsetting joints of the 

 N-S system, so that the upper mass was moved eastward 

 relative to the lower mass. This offset of the joints is 

 only the apparent displacement. The cliff faces very 

 close to due south, its trend being E-W, with no dip in 

 either direction which could be detected with a Brunton 

 clinometer or a telescope clinometer even by distant sight- 

 ing. As the streams always hug the north sides of their 

 courses it is to be inferred that a slight northerly dip 

 must be present. Taking the direction of pressure as 

 previously calculated at an average of about 10° west of 

 south, the chief movement will be in a general N-S direc- 

 tion, the E-W component representing only the very small 

 part played by the 10° deviation from N-S. As the fault 

 does not persist for any very great distance it is safe to 

 infer that the maximum displacement is nowhere great. 

 This locality is about two miles north of the crest of the 

 anticline at Portland Pt. and hence on the northern limb, 

 the dip of which is very far from constant. It appears 

 to be located on a second horizontal area, another level 

 district occurring about 100' higher and half a mile nearer 

 it. Instead of being due to pressure this fault may possi- 

 bly, though not at all probably, be due to local relaxation 

 and hence belong to a type intimately connected with val- 

 leys and which will be discussed in connection with the 

 wedge fault block to follow. 



Mr. G. C. Matson in an article on "Peridotite Dikes 

 near Ithaca, N. Y. " 7 calls attention to several dikes not 

 here considered. One group of four is above the high 

 fall over the Genesee shale, in a tributary to Salmon Cr. 

 just northeast of Ludlowville. * l Three of these have been 

 faulted ; the fourth does not reach up to the fault plane. 

 The amount of displacement is about two feet. ' ,s From 



7 Jour. Geol., vol. 13, p. 265, 1905. 



8 Ibid. 



