POSTGLACIAL FAULTS OF EASTERN NEW YORK I9 



but the roadway has been much worn and weathered and precise 

 measurements are unattainable and were not attempted. 



The two tables show a closely similar rate of dislocation for 

 a given distance within the belt. Thus in the first case there is 

 a displacement of 7.67 inches in a distance of 11 feet, 10 inches, 

 and in the second case a displacement of 7.21 inches in a dis- 

 tance of II feet, 6 inches, an average of 7.44 inches in a distance 

 of II feet, 8 inches, nearly 1.9 inches a yard, or 336.7 feet a mile. 



The apparent uplift on the east at this locality, basing the 

 estimate upon the two measured portions of the sections and 

 upon that which was estimated only amounts to nearly 2 feet 

 within little more than the width of the highway. If allowance 

 is made for the very minute fractures revealed by a close exam- 

 ination of the glaciated surface with a pocket lens, it seems a 

 conservative estimate to state that the dislocation at this locality 

 exceeds 2 feet of vertical displacement. 



The faults at this locality lie with rare exceptions in the 

 cleavage planes whose strike is n. 30° e. and whose dip is 60° e. 

 The glacial striae run n. 10° w. 



At a point on the roadside where the slates have been cut 

 away in grading the road, chance was given to observe the 

 appearance of the cleavage faces for a foot or more below the 

 surface along the plane of a fault. Although the vertical move- 

 ment on this plane was less than an inch, well formed vertical 

 slickensides were found. The surface of the slickensides was 

 dull and water stained without that polishing which is character- 

 istic of faults along which movement has recently taken place. 



Near the northern end of the exposure on the east side of the 

 road two small parallel faults were seen overlapping [see fig. 5], 

 one dying out southward, the other northward, as in the accom- 

 panying figure. At another point at this locality a fracture cuts 

 the slaty cleavage obliquely, but the downthrow is here, as else- 

 where in this vicinity, on the west. 



Fractures near Pumpkin Hollow. Three fourths of a mile 

 northwest of Pumpkin Hollow, at a point about a mile west of 

 Copake Lake in the town of Taghkanic, postglacial fractures occur 

 in slates on the western slope of a hill. The glaciated surface 

 was at the time of my visit exposed in small areas of outcrop. 

 Within a distance of 200 feet up the slope I made a rough meas- 

 urement of 17 inches of displacement by small faults, varying 

 in individual cases from a quarter of an inch up to nearly 3 



