GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 85 



Some of the slates within the quadrangle are shown by these 

 discoveries to be younger in age than the so-called Trenton con- 

 glomerate of the area. Some may be contemporaneous and prob- 

 ably are;\ others are possibly much younger. The relations 

 farther north, in Washington county, have shown that the Lower 

 Cambric slates have been brought to the surface by faulting, but 

 within this area it has not proved possible to determine this. On 

 the whole, it does not seem probable. 



The general problem of the slates is postponed until several fea- 

 tures have been stated in detail. 



Red slates. Red slates with green bands of varying thickness 

 may be traced at intervals diagonally across the ciuadrangle, along 

 the prevailing strike, from Matteawan to the northeastern corner of 

 the area. Their regularity of recurrence indicates that an important 

 stratum is involved in the folding. The main stratum of these red 

 slates as shown in several places has a fairly uniform thickness. 

 Thinner red bands have rarely been noted in the more common 

 grayish-black members of this formation. 



In the town of Matteawan red slates with green bands form thick 

 masses along the banks and bed of Fishkill creek as far as the 

 carpet mills at Wolcottville, and north of here at Glenham along 

 the road from Matteawan to Fishkill Village, just west of the Glen- 

 ham gneiss belt, ledges of these rocks are abundant. The red slates 

 are locally called the " paint rock." Farther north along the strike 

 they were noted north and south of the road from Fishkill Village 

 to Chelsea and along the road from Swartoutville to Flughsonville. 

 A thick band occurs along the New York Central Railroad track 

 one-fifith of a mile south of Paye's clay pits and a similar band just 

 north of the station at Chelsea. They were not noted farther north 

 along the river section. The slates at Chelsea continue northeast 

 along the strike and appear one mile north of New Hackensack 

 along Wappinger creek, and again near Manchester Bridge and at 

 Overlook; also frequently along the roads from Pleasant Valley to 

 Moores Mill. At the north they appear oftener, chiefly because of 

 the more frequent and larger outcrops of the slates and the thinner 

 covering of surface material. 



There are reasons for thinking that the slates form a synclinal 

 fold west of Matteawan and possibly the red slates at Matteawan 

 and south of Paye's pits respectively represent the east and west 

 limbs, while those at Chelsea may represent the western limb of 

 the succeeding anticline. 



