GEOLOGY OF THE NEW YORK CITY AQUEDUCT 



41 



Ewen as a single unit. If any distinct formation is to be recog- 

 nized it would be on the basis of transitional faunal character, 

 placing the fossiliferOus upper 100 feet in the Oriskany transition 

 and confining the name Port Ewen to the rather unfossiliferous 

 and concretionary, shaly, argillaceous limestone of the lower 100 

 feet. 



/ 





Fig. 3 Spirifer arenosus (Conrad), one of ihe characteristic index fossils of 

 tie 0-::;kany occurriag in the Port Eweii-O.iakany Lraiibition 



This transition rock is strongly bedded, argillaceous and 

 silicious limesione, very quavtzose in certain layers, but there 

 are no exposures in this area that would be called sandstones. 

 Fossils are abundant and show marked Oriskany peculiarities. 

 Those of most characteristic relations are : Hipparionyx 

 proximus, Leptostrophia magnifica, Spirifer 

 m u r c h i s o n i , Spirifer a r e n o s u s , P 1 a t y c e r a s 

 nodosum. Strop hostyl us expan'sus. 



