GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 69 



On the north side of the road near the turn is an old quarry. No 

 fossils were found, but the quarry rock resembles the dark blue 

 mud rock of the Trenton. 



Faulted block number 5. Between this block and number 4 

 is an interval of lowland forming the present flood plain of Wap- 

 pinger creek. This interval is probably underlain by the slate which 

 was dropped down in here and which, in connection wdth faulting, 

 produced a line of weakness which the base-leveling forces early 

 reduced and which has been perpetuated by the present stream. 

 Outcrops are concealed in the flood plain interval except near the 

 southwest corner of block number 4. At this point there is a large 

 patch of slate that has been planed down and which disappears 

 under the alluvium at the southeast. 



The rather steep slope on the southwest side of this interval is 

 taken as representing the northern margin of block number 5. The 

 eastern and western margins are approximately those shown on the 

 map, while the southern margin appears to be along the great fault 

 line at this point. Surface deposits conceal the northern margin, 

 but outcrops are occasional to the north of the Poughkeepsie-New 

 Hackensack road, and almost continuous along it from east to west. 

 The western margin is easily followed along the crossroad to the 

 Spackenkill road until the limestone is cut off by the fault. No 

 fossils were found in this patch of limestone and the lithology did 

 not help in making any provisional correlation with other localities. 



Faulted block number 6. This small strip lies south of the 

 Spackenkill road and is a little over a mile long and less than one- 

 fourth of a mile wide. It is separated from the main central strip 

 by a narrow band of the slates which form conspicuous ledges for 

 a few hundred yards south of the Spackenkill road and are trace- 

 able along the edge of the swamp through the woods to the southern 

 termination. At the south the limestone disappears abruptly 

 beneath the slates just north of the old barn and probably is faulted 

 here. At the north it also gives place to the slates north of the 

 Spackenkill road and is certainly faulted here. The limestone of 

 this strip forms a conspicuous ridge throughout its length. No 

 fossils were found although a careful search was made, particu- 

 larly near the southern extremity. 



Faulted block number 7. This block lies farthest east of all. 

 The boundaries are best indicated by the map. The entire strip has 

 a northeast-southwest bearing which closely follows the general 

 strike of the limestone. It is about one and one-fourth miles long 

 and one-fourth of a mile wide. At the north it disappears beneath 



