GEOLOGY OF SARATOGA SPRINGS AND VICINITY 8l 



In the matrix there was also obtained a specimen of Plectam- 

 bonites pisum, a species known from the Rysedorph Hill 

 conglomerate at Rysedorph hill. As this conglomerate contains 

 pebbles of various ages, from the Georgian to the Mohawkian, 

 like that of Rysedorph hill, and lies in the northern continuation 

 of the latter and apparently, also as this latter, above or in the upper 

 Normanskill shale, we have identified the Bald Mountain con- 

 glomerate with the Rysedorph Hill conglomerate.^ The occurrence 

 of Plectambonites pisum common to both outcrops also 

 supports this view. 



We surmise that the Trenton fossils formerly recorded from the 

 limestone north of Bald mountain came from this conglomerate. 



The conglomerate at Bald mountain may reach a considerable 

 thickness; in the quarry it is in one place over 20 feet thick, but 

 it is impossible to say how much the folded condition contributes 

 - .his thickness. Along the brook northwest of Bald mountain we 

 observed the following section from east to west, the beds being 

 nearly all vertical : 



1 Cambric shale 



2 Covered 90 feet 



3 Limestone with some quartzite and breccia 55 feet 



4 Covered 270 feet 



5 Conglomerate with large pebbles 45 feet 



Trenton fossils and calcareous matrix 

 Rysedorph Hill conglomerate 



6 Calcareous shale and shaly nodular limestone 



(Georgian) 200 feet 



7 Covered 70 feet 



8 Conglomerate with large pebbles 75 feet 



9 Covered 



It is possible that the conglomerate bed in no. 8 is folded upon 

 itself, and in no. 5 the simple thickness of the bed is exposed. It is 

 there about 45 feet thick. 



While this conglomerate in its outcrops adjoins the Bald Moun- 

 tain limestone, its fossils indicate that it is younger than the typical 

 Normanskill shale and intervenes in age between this and the Snake 

 Hill shale. It therefore should be separated from the Bald Moun- 

 tain limestone by the Normanskill shale. On Rysedorph hill the 



1 Ruedemann. R. Trenton Conglomerate of Rysedorph hill. N. Y. State 

 Mu9. Bui. 49, p. 3. 



