S6 



l^eW YORK STATE MUSEuM 



sandstones (very thick) (Or- 

 dovicic) more than 2000 feet 



(23) Wappinger Hmestone (1000 feet) 



(in part Cambric and in part 

 Ordovicic) 



(24) Poughquag quartzite (600 feet) 



(Cambric) 



UNCONFORAIITY 



Group f Cainbro-Ordovicic formations 

 {22) Hudson River slates, shales, and.^ Especially prominent as 



surface formations in 

 the S h a w a n g u n k 

 range, the Wallkill 

 valley, and the region 

 eastward and south- 

 ward to the High- 

 lands, on both sides 

 of the Hudson 



Group g Later crystallines (South of the Highlands) 

 (Uncertain age) 



(i) The IManhattan schist, a thor- "] 

 oughly and coarsely crystalline 

 sediment of uncertain age — 

 generally supposed to be equiva- 

 lent to the Hudson River slates, 

 (Ordovicic) but here separated 

 without necessarily raising that 

 question because of their very 

 different physical and petro- 

 graphic character 



(2) Inwood limestone (or dolomite), 



a magnesian crystalline lime- 

 stone of uncertain age, generally 

 supposed to be the equivalent of 

 the Wappinger (Cambro-Ordo- 

 vicic), but here enumerated sep- 

 arately without necessarily rais- 

 ing that question because of 

 their very different lithologic 

 character and associates 



(3) Lowerre quartzite, an occasional 



quartzite of imcertain relations , 

 and very limited development J 



Confined to the region 

 east of the Hudson 

 river and south of 

 the Highlands proper, 

 occupying the region 

 from the Highlands 

 to Long Island 



