GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 9 1 



Fig. 26 Overthrust east of John Fleet's. A, limestone conglomerate; B, silicious limestone; 



C, slate; F, fault 



When seen from above the conglomerate is coarse, but when 

 examined along the edges of the eastwardly dipping beds the 

 pebbles are seen to be squeezed out into stringers, so that the 

 apparent coarseness can not represent the original condition. The 

 dip is about 20° e. and the strike about n. 10° e. The calcareous 

 quartzite was not seen in actual contact with the conglomerate, but 

 is undoubtedly conformable. At the east the former is followed 

 by the slates. Solenopora com pacta, showing the char- 

 acteristic very fine lines, was noted in the conglomerate. The 

 quartzitic rock outcrops at intervals to the south for one-fourth to 

 one-third of a mile, but gradually dies away. At the north the 

 series ends more abruptly. 



The conglomerate at the last mentioned locality of those which 

 have just been described is undoubtedly the equivalent of that 

 which at Pleasant Valley and Rochdale overlies the eroded Beek- 

 mantown, and there can be little doubt but that the conglomerate at 

 the other localities is also the same. There is shown again the 

 general tendency for the older rocks to be faulted up among the 

 younger ones. 



Summary of features shown by the conglomerate and associ- 

 ated rocks. At Pleasant Valley and at Rochdale the con- 

 glomerate and overlying or interbedded blue limestone resting on 

 the eroded Beekmantown are prominently developed. At Rochdale 

 the series is from 70 to 100 feet in thickness and at Pleasant Valley 

 it is apparently about the same. At Sleight's quarry near Man- 

 chester Bridge the conglomerate and blue limestone is from 20 to 

 30 feet in thickness, but certain faulting here makes it unsafe to 

 regard this change as marking a thinning of the limestone. Far- 

 ther south along the Wappinger creek belt one can get no idea of 



