GEOLOGY OF THE VICINITY OF LITTLE FALLS 



45 



drag, it also throws to the west, as does the main fault, and it is 

 likely a small branch of the latter. It would indicate that the 

 dying out of the fault is probably produced in part by branching. 

 Between these two points a bend in the creek carries its east 

 bank back against the fault plane, which here forms a nearly per- 

 pendicular cliff some SO feet in hight, rising directly from the 

 creek margin. The topographic map is not quite accurate here, 

 so that it is impossible to properly show this feature upon it, an 

 excessive bend and an incorrect course being required to bring the 

 fault to the creek on the map as it stands. The fault plane con- 

 tinues at the margin for only a few yards, then runs diagonally 

 up the cliff face, updragged Utica shale appearing at the base, 



Scale 



So ft 



Fig. 8 Section across East Canada creek at the point where the Dolgeville fault 

 forms the east bank. TJ=Utica shale, T=Trenton limestone, L=Lowville limestone 

 and B=the Beekmantown beds. The fault breccia is also shown. The section crosses 

 the east wall at the right in plate 6. 



and running constantly higher, till it forms the entire hight of the 

 cliff. The features are magnificently shown, but are unfortunately 

 difficult to photograph satisfactorily, plate 7 showing them as 

 well as it is possible to bring them out. Figure 8 gives a scale 

 drawing of the section here. A fault breccia from 2 to 5 feet wide, 

 consisting of a multitude of angular fragments of all sizes, in 

 which Beekmantown material largely predominates, but with a 

 considerable contribution from the Lowville and Trenton als'o, 

 embedded in a black, fine grained matrix, which seems largely of 

 I'rica origin, occurs here. There is a layer of chert near the sum- 

 mit of the Beekmantown here, as elsewhere, and this has naturally 

 



been a large contributor to the breccia. It has been also largely 

 impregnated with pyrite or marcasite, which forms at times 

 nearly the entire .matrix, and whose decomposition and oxidation 



