OVERLAPS. 391 



Whether the fault passes between the slate and quartzite, or the slate 

 and limestone, northward, is not exposed, but the former appears more 

 probable. 



There is a small fault in the Green Pond quartzite on the southeast 

 shore of Greenwood lake, as shown in section VII, but it is apparently 

 only a local slip. Possibly it has greater throw southward and cuts off 

 the several formations in the northern end of Kanouse mountain. 



Overlaps. — There is a very great amount of overlapping in the Green 

 Pond to Skunnemunk belt, and the phenomena throw interesting light 

 on the oscillations of level and other conditions during the deposition 

 of the several formations. I have alluded above to the difficulty in dis- 

 criminating between overlap and overthi'ust, but the relations of the prin- 

 cipal overlaps appear to be clear. 



The Cambrian limestone lies on or against the crystalline rocks, with 

 more or less arenaceous material intervening. It is overlapped by the 

 Hudson shales in New York, which also extend to the crystalline rocks 

 and abut against them. This relation is clearly exposed at many localities 

 in Orange county, notably along the small crystalline knobs west of 

 Skunnemunk mountain, which were islands in the earlj^ Hudson seas. 

 A very fine exhibition of the contact of the shales and gneiss was found 

 in the south bank of the creek at the south end of Woodcock hill, as 

 shown in the second section from the top in figure 6. 



The Green Pond conglomerate lies directly on the crj^stalline rocks 

 over a wide area south of Newfoundland, and then extends across the 

 edges of the Cambrian limestone to and over supposed Hudson shales 

 south of Greenwood lake. In Pine hill it overlies the Cambrian lime- 

 stone, with strong unconformity in dip. and about Cornwall Station it 

 overlies the Hudson shales. 



The Longwood shales are not known to overlap, for they merge into 

 the upper part of the Green Pond rocks in all the exposures. The Hel- 

 derberg limestone usually lies on and merges into the Longwood shales, 

 but on the west side of Bellvale and Skunnemunk mountains it lies 

 unconformably on Cambrian limestone, with no possibility of an inter- 

 vening fault. 



The Oriskany quartzites and conglomerates lie on the Helderberg lime- 

 stone in New Jersey, at Cornwall Station, and in the locality two miles 

 west-north^vest of IMonroe, but it overlaps or possibly is overthrust on 

 older formations for the greater part of its course west of Bellvale and 

 Skunnemunk mountains. Near the line of section V, plate 17, it lies on 

 the Hudson shales, but, as suggested a number of times above, this may 

 possibly be due to overthrust. In the small areas lying against the 



LV— Bor,i. Geol Soc. Am., Vor,. 5. 1893. 



