W. 13. DWTGHT. 149 



tions will soon be made in the nomenclature and classi- 

 fication of much of the rock now called such in the 

 United States ; it is not unlikely that the phenomena of 

 our Wappinger limestone, as now developed, will have 

 much to do in determining such a reclassification. 



I will close this part of the subject by saying that at 

 the present stage of investigation, (1) this lower limestone 

 still seems to me more properly referable to the so called 

 " calciferons " than to any other formation, and that 

 I will continue for the present to give it that name pro- 

 visionally ; (2) that if not calciferons, it will probably 

 prove to be a member of the Canadian rather than the 

 Trenton period — and may not unlikely prove to be the 

 Chazy group ; (3) that any extended discussion of this 

 question is scarcely profitable until these fossils are 

 fully studied and described ; (4) that whatever the future 

 decision as to the horizon, the fossils themselves will re- 

 main remarkable and important. 



Before leaving the stratigraphical questions, it is 

 proper to say a few words as to the relative extent and 

 exposures of the two limestones. The great mass of the 

 limestone along the Wappinger creek, from Willow 

 Brook, at least, to New Hamburgh, appears to be cal- 

 ciferous, and shows its fossils in many places all along 

 this line. On the west side of the Hudson, from Marl- 

 borough to three miles southwest of Newburgh, the 

 mass of the rock lithologically appears to be calciferons, 

 though I have entirely failed to find a single calciferons 

 fossil in all that region. The Trenton rock and fossils 

 are much more limited in their exposures, and yet there 

 are long stretches of this formation usually lying on the 

 eastern sides of the limestone ridges. A little Trenton 

 crops out at Wallace's quarry, Salt Point, ten miles 

 northeast of Poughkeepsie. It appears largely at Pleas- 

 ant Valley, six miles from this city, then at Rochdale. 



and for about one mile south of that place. 



101 



