4 NEW YORK STATE MUSEUM 



age. This conglomerate bed is intercalated in the so called Hud- 

 son river shales discussed in a previous paper and is thus of still 

 farther interest in its bearing on the question of the age of those 

 shales. 



A perusal of the early literature of the New York geologic sur- 

 vey leaves no doubt that this same hill with the capping limestone 

 conglomerate once played a very interesting and important role 

 in the bitter struggle over the Taconic problem. 



Dr Emmons was probably the first to notice the locality and 

 collect its fossils; for Hall, in Paleontology of New York, 1:35, 

 described among the Chazy fossils a cephalopod as Ortho- 

 ceras bilineatum, and added : 



* An examination of this specimen since the plate was engraved 

 convinces me that it is identical with O. bilineatum of the 

 Trenton limestone. This specimen was given me by Dr Emmons 

 as coming from the Calciferous sandstone at a locality 2 miles 

 east of the city of Albany. An examination of the spot has con- 

 vinced me that the rock in question is the Trenton limestone 

 thrust up through the Hudson river slates. The association of 

 fo'ssils as well as other circumstances prohibit its reference to 

 the Calciferous sandrock. 



Dr Emmons, in his endeavor to defend the Taconic system 

 against the aggressions of nearly all his contemporaries, con- 

 sidered the stratigraphy of this locality as of special importance 

 for the demonstration of his assertion that the Siluric beds lie 

 unconformably on the Taconic. In his last defense of his 

 cherished object of research, contained in AmeHcan geology, 1855, 

 pt 2, p. 72, a section of Rysedorph hill 1 is given, which is copied 

 here with the following description of the stratigraphic relations. 



At the milldam, the blackish sandstones of the Hudson river 

 dip also east; half a mile further sandstones again crop out, 

 dipping steeply to the west. Just beyond, the green Taconic 

 slates dipping e 10° s support a heavy mass of Calciferous sand- 



1 Dr Emmons calls the hill Cantonment hill. Inquiries among the occupants of the neighboring 

 farms brought out the fact that the next hill succeeding in southerly direction was formerly called 

 Cantonment hill on account of a military encampment on it during the war of 1812, and this term has 

 now been perverted into Catamount hill, the present name of that prominence ; while the hill 

 described by Dr Emmons passes now under various names, as Sugar Loaf hill, the Pinnacle, Ryse-. 

 dorph hill, etc. As the last name has been adopted on the topographic map of the U. S. geologic 

 survey, it is retained in this paper, though no longer in popular use. 



