GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 65 



Summary and conclusion. The absence of the Trenton con- 

 glomerate at places along the eastern margin of the central strip 

 might be interpreted as the result of faulting and, in any event, is 

 probably due in part, at least, to faulting. 



The presence of Tetrad ium cellulosum in the Pough- 

 keepsie and Eastern Railroad cut at Pleasant Valley is noteworthy. 

 Professor Clarke^ has indicated that elsewhere this fossil is charac- 

 teristic of the Lowville. The Trenton conglomerate at this locality 

 is apparently a few feet above the beds carrying this fossil. This 

 would seem to indicate that the Lowville might have been deposited 

 here. Doctor Ruedemann- has discussed the Trenton, as descrbed 

 by Dwight, as probably not lower than Midtrenton in age. 



The examination of this strip leaves one in great doubt as to how 

 to represent its structure. It is certainly very different from Pro- 

 fessor Dana's early representation as a simple fold.^ It is best inter- 

 preted as belonging to the same thrust that pushed the western 

 strip on the slates, but as the map shows the limestone broke both 

 along and across the strike and at the south was . pushed farther 

 west, apparently feeling the influence of the Highlands mass. 



MISCELLANEOUS FAULTED BLOCKS OF THE WAPPINGER CREEK BELT 



Several smaller limestone masses, each of which can be reason- 

 ably shown to be a detached and separate block, forming an inlier 

 in the slates, are scattered to the east of the central strip along its 

 middle portion. The mantle of the surface deposits at times 

 greatly obscures their exact relationships to the slates, but as a rule 

 the field relations leave scarcely any doubt of their inlying character. 

 In most, if not all cases, these relations point to faulting, both 

 along and across the strike between the limestone masses and the 

 slates which surround them. 



These blocks will be described separately and will be designated 

 by numbers from north to south. The occurrence of these faulted 

 blocks of limestone to the east of the central strip seems to be 

 directly due to the thrust which carried the limestone of this belt 

 over the slates. They have been left, stranded as it were, behind 

 the main mass. 



1 Guide to the Fossilif erous Rocks of New York State. N. Y. State Mus. 

 Handbook 15, p. 9. 



2 Hudson River Beds near Albany and their Taxonomic Equivalents. 

 N. Y. State Mus. Bui. 42, 1901, p. 501. 



^Amer. Jour. Sci., May, 1879. 17:382. 



