Wappinger Valley Limestone of Dutchess Co., JV. Y. 29 



with the Trenton, a finely fossiliferous ledge of which closely 

 adjoins it on the east side of the ridge. 



Later researches in the limestone more to the northward de- 

 veloped an additional locality quite fossiliferous, and possessing 

 some very interesting features. It is about half way between 

 Pleasant Valley and Salt Point, and very near Schoolhouse 

 No. 12, just at the point where a branch road from the main 

 road towards Wappinger's Creek, crosses the limestone ridge 

 with a sharp turn to the north. Here, in the cut along the 

 road and in Mr. Paul Flagler's fields on either side of the road, 

 can be found excellent specimens of Lingulepis pinniformis y 

 and of an interesting Obolella which is apparently a new spe- 

 cies. Specimens found here are quite finely preserved. This 

 locality is seven and a half miles northeast from Poughkeepsie, 

 and about the same distance northerly from the Smiley locality. 

 This ledge can be traced for half a mile or more to the north 

 of the schoolhouse, though it has not shown fossils much in 

 this direction ; at Wallace's quarry, however, a mile to the 

 northeast, fossiliferous Potsdam again crops out at the eastern 

 base of the high ledge of Trenton and Calciferous limestone 



D O 



close to the farmhouse. This increases very much the difficulty 

 of solving the previously difficult problem of the stratigraphy 

 of Wallace's very interesting quarry. While my earlier ex- 

 aminations of the limestone between Salt Point and Pleasant 

 Yalley have produced undisputable evidence of the presence 

 there of Trenton strata, and of those which I have considered 

 to belong to the Calciferous. it is now proved that the Potsdam 

 is also present there ; there are reasons for believing that it may 

 be very extensively represented in this portion of the belt. 



The existence of Potsdam strata of at least the Saratoga 

 County horizon, in considerable abundance, having been thus 

 thoroughly established, the next point of inquiry which would 

 naturally suggest itself, would be as to the possible presence 

 also of pre-Potsdam beds. The width of the limestone belts 

 where the Potsdam rocks have been found in conjunction with 

 those of higher groups, is hardly great enough to lead one to 

 expect to find lower strata; they would be likely to exist, if 

 anywhere, along the margins of the Archasan mountains of the 

 County, where the gneiss is overlain by quartzyte and lime- 

 stone strata. 



On June 24, 1884, up to which date no paleontological evi- 

 dence of strata even as low as the Potsdam had been found 

 here, Mr. S. W. Ford and the writer made a short trip between 

 two trains to the base of Stissing Mountain, seventeen miles 

 northeast of Poughkeepsie. We desired to take a look at the 

 quartzyte immediately overlying the gneiss, and which for strat- 

 igraphic reasons solely, has long been supposed to be Potsdam 



