TRENTON CONGLOMERATE OF RYSEDORPH HILL 5 



stone, a, and slaty Trenton limestone. Viewing the position of 

 all the rocks, we find that there is an anticlinal axis running at 

 the base of the ridge at f, supporting the limestone. The anti- 

 clinal is on the line of the great Hudson river fault. The lime- 

 stone, which is the most important mass, rests unconformably 

 upon the Taconic slates bb. 



Dr Emmons hence regarded the slates composing the hill as 

 belonging to his Taconic system, and the Siluric beds, which he 

 insisted were Calciferous and Trenton, 1 as lying unconformably 

 on the slates; while Hall, later relinquishing his first view of 

 the upthrusting of the Trenton block, considered the limestone 

 conglomerate to be interlaminated in the Hudson river series. 

 This view is met by Emmons with the following pertinent 

 remark : 2 



Now some paleontologists are willing to admit that a few 

 fossils may go up from the Trenton into the Hudson river 

 series, but I believe that this is the first time that a paleontolo- 

 gist is willing to transfer the whole of the Trenton limestone 

 with all its contents into a higher group. 



From a note in the description of the fossils in the cited 

 work of Emmons it appears that this investigator insisted on 

 the Calciferous age of the O r t h o c e r a s b i 1 i n e a t u m 

 described by Hall from that locality; for 3 it is added after the 

 description, " Calciferous sandstone, Greenbush ", and remarked, 

 " Trenton limestone thrust up through the Hudson river 

 slates!!" (the exclamation marks those of Emmons). And it 

 is farther stated that the figure given by Hall of the O. 

 b i 1 i n e a t u m from Greenbush differs from specimens from 

 the Trenton. It is insinuated that Hall identified the species 

 as a Trenton form to avoid admitting the presence of the Gal- 

 ciferous sandstone, for "to admit the existence of the Calciferous 

 sandstone below the Trenton at this place would be equivalent 

 to the admission of the Taconic system." 



i Emmons recognized the derivation of the pebbles from several formations as is evident from his 

 remarks on this locality in the Agriculture of New York. 1846. 1:57, where are cited as found by him 

 in the limestone bed; Maclurea, Bellerophon bilobatus and "masses bearing the char- 

 acter of the Birdseye limestone " and it is concluded that " all these facts put together indicate that 

 this mass of limestone is a mixture of all the lower limestones of the New York system; that they 

 meet in this mass though it is by no means extensive." 



2 Am. geology. 1855. pt 2, p. 72. 



'Am. geology. 1855. pt 2, p. 149. 



