STRUCTURE. 



387 



for about three miles, and there is also a small mass of conglomerate 

 overlying the limestone about three miles south of the lake. These beds 

 have been referred to by several observers, and Smock ^ has given a sec- 

 tion in Avhich some of their relations are shown. Merrill j included the 

 upper conglomerate in the Green Pond formation, and this was also sug- 

 gested by Smock, but I found that there is an intervening mass of the 

 supposed Hudson slate referred to on page 386. The relations are shown 

 in figure 4, which is near the line of section VIII, 

 plate 17, and through the beds in which Mr Wal- 

 cott found the Olenellus. 



Mr Foerste visited the locality in 1893, and he 

 has stated the opinion ;j: that the limestone was the 

 " magnesian limestone " of northwestern Ncav Jer- 

 sey and the underlying quartzite the " Olenellus " 

 quartzite. He found no fossils. 



Structure. 



Flexures. — The general structure of the region is 

 synclinal, but there is considerable diversity in 

 the shape of the main flexure and there are 

 several subordinate flexures, notably in the New- 

 foundland region. The strike is northeast by 

 north in Bellvale mountain and the region north- 

 ward, but at Monroe there is an abrupt change 

 in trend to northeast, which continues through 

 Skunnemunk mountain and northward. 



In figure 5 I have attempted to show the nature 

 uf the flexures by a succession of sections draAvn 

 at the base of the Monroe shales. 



The variations in steepness and pitch are, I think, 

 the only noteworthy features of these flexures. 



The close folding of the northern portion of the general syncline is 

 exhibited in the northern end of Skunnemunk mountain and northward, 

 and in Bellvale and Bearfort mountains. The open portion of the 

 sjaiclinal is in the central and southern portions of Skunnemunk moun- 

 tain and the region from west of Newfoundland to Milton. The flags 

 and shales in the southern end of Bellvale mountain exhibit a gentle 

 synclinal, although there is much slaty cleavage and the dips are not al- 



•= l.oe. eit., p. 52. 

 t Loc. eit., p. 115. 

 JJLoc. eit.. p. 441. 



FiGURK 5. — Flexures of 

 the Green Pond- Skunne- 

 munk Mountain Belt {look- 

 ing northeast). 



