FAULTS G-G, H-H AND I-I. 293 



River limestone exposures north of F-F, so tluxt a fault of great throw 

 is indicated if tliis outcrop is taken as indicative of the normal relations 

 along the fault-line. There are, however, at least two other outcrops of 

 Black River limestone, and perhaps more, which occur at points farther 

 south along fault A-A, hetween the Potsdam west of the fault and the 

 Chazy east of it, and it may he that this outcrop under consideration 

 should be classed with them as an extremely aberrant mass merely in- 

 dicative of the great shattering which has taken place along A-A. If 

 this be accepted as the true ex})lanation, the only evidence we have of 

 a fault at F-F is the sudden disappearance at that line of the ridges 

 of Chazy limestone which lie north of it. 



Fault G-G. — To the south of this knoll of Black River limestone no 

 outcrojis have been noted for a distance of half a mile, when the section 

 exposed along the river at Chazy village, and in the village itself, is 

 reached — a section showing the middle and upper Chazy followed by 

 the Black River. The absence of outcrops makes the presence of a fault 

 here purely conjectural, and the data at hand could be equally well ex- 

 plained by the jiresence of a synclinal trough running from fault F-F to 

 the outcroi)S at Chazy village. The fault is preferred as the explanation 

 merely because no other fold of the kind is known in the township. 



Fault H-H. — Brainard and Seeley's detailed map of the vicinity of 

 Chazy village commences on the north at the river section just men- 

 tioned, and extends thence for a mile to the south and a mile and a half 

 to the southwest, showing faults H-H and I-I.-i^ The map is exact in all 

 respects, and may be profitably consulted for details. The fault-line H-H 

 is occupied by the river for a portion of its length. Beyond the point 

 where the river leaves it, its course is clearly indicated by the abrupt 

 cutting off of the ridges of rock on the opposite sides of the line and by 

 the heavei as well as by the change in amount of dip. The Black River 

 limestone south of the fault lies loO yards west of the same stratum north 

 of the fault, as measured normal to the strike, or 250 yards distant along 

 the fault-line. The south is therefore the thrown block, and the vertical 

 displacement is not far from 200 feet. 



Fault I-T. — The strike swerves somewhat toward the west as this fault 

 is approached, and the fault itself has a more nearly north-and-south 

 trend than the others of its class. The Black River limestone west of 

 the fault is heaved 250 yards to the south, a greater lateral distance tlian 

 the heave of \\-\l^ Init tlie dip is correspondingly less. A tlirow of about 

 the same amount as that of II-H is thereby indicated, but in th<! reverse 

 direction, the northeast being the thrown block. In other words, the 



•Am. Geologist, November, 1888, p. .^2r,. 



fGeikie: Text-book of Geology, third edition, p. ')M. 



XLI-Bi'i,i,. Gkol. Soc. Am.. Vol. o. 18<»4. 



