REPORT OF THE DIRECTOR I916 1 55 



zone of the Chazy which now shows here, had ah'eady amounted to 

 450 feet, and the total displacement is equal to this figure plus the 

 distance from the base of the Trenton to the zone of that formation 

 which now rests against the Chazy at this place. This will in time 

 be determined, but a necessar}^ factor in this determination will be 

 the careful collecting and comparison of the fossils from all the 

 exposed Trenton beds of the Champlain valley or from borings 

 which may subsequently be undertaken in some portion of the 

 region. 



So far, this fault has had much to tell us, but we have as yet 

 translated only a very small part of its story. If we carefully 

 examine the slickensided Chazy wall we shall find that the scratches 

 produced by the movement of the other wall against this do not 

 dip to the north, as the Chazy wall itself does, but their lower ends 

 are carried easterly. We must remember that the scratches we 

 now see were among the last to be made for no doubt this " slate " 

 was used many times and the older scratches removed by additional 

 grinding. Here we state a new problem. If the last large move- 

 ments of the Trenton were still downward then it also moved east- 

 ward at the same time. How ma}^ w^e account for such an east- 

 ward movement? The truth of the matter seems to be that we can 

 not; and if we study the locality a little more closely we may find 

 that, in its later movements over this wall, the Trenton moved 

 westward and therefore upward. 



Walking along the Trenton beds which are . exposed for about 

 one-half of a mile to the north of the steamboat landing, we shall 

 note that their slope (dip^ the geologists call it) is easterly. South 

 of the steamboat landing we may notice a marked change in the 

 direction of this dip and as we approach the exposure shown in 

 figure 4 we shall find that the dip is decidedly westerly. The Chazy 

 rocks on the south, however, dip easterly. If this condition of 

 things continues westerly we should soon have the base of the 

 Chazy resting against rocks well up on the Trenton side. In other 

 words, our fault with a displacement of say 600 feet at the lake 

 shore might have a displacement of a thousand feet where the rail- 

 road crosses it. This is evidently a rotatory fault, or at least it 

 became such near the end of its activity. Now if we will face the 

 Chazy wall we may see that the twist of the Trenton side must 

 have been clockwise, which would indicate an upward and west- 

 ward movement of its beds where exposed in Haven bay. The 

 scratches would partake of the nature of broken arcs of great 

 circles, the axis of rotation being situated at some deeply buried 



