HUDSON RIVER BEDS NEAR ALBANY 49T 



The most interesting discovery of Whitfield's is that of the 

 presence of shales of Tfenton age among the shales of the Hudson 

 valley. The writer has carefully compared specimens of the grap- 

 tolite in question found at the arsenal yard and preserved in the 

 state museum with the D. amplexicaulis found in the 

 Trenton limestone at Middleville and is convinced of their iden- 

 tity. Besides this graptolite other fossils have been found in the 

 shales and calcareoius eiandstones ('not limestone) of south Tl'oy 

 and the neighborhood of the arsenal which more firmly establish 

 Prof. Whitfield's discovery. 



The supposed homotaxy of the Normans kill fauna with that 

 of the Utica shale is based on the occurrence of four graptolite® 

 in both faunas. Of these the presence of Didymograptu^ 

 serratulus in the Utica beds has not been verified by other 

 collectors and is doubted by Lapworth and Gurley; Hall's 

 Diplograptus pristis, however, is partly identical with 

 Hall's D. quadrimucronatus, which is very common at 

 Fort Plain as everywhere in the Utica shale, and which at that 

 time was considered also by Hall as occurring only at the locality 

 from which it was first made known (Lake St John, Canada), 

 and partly identical with Diplograptus foliaceus^ 

 Murchison.^ 



The two forms, D. f o 1 i a c e u s and D. q u a d r i m u~ 

 cronatus, are not always easy of separation, when com- 

 pletely flattened in the shales; and the writer also has, follow- 

 ing HalPs example and identification, described colonies of D, 

 quadrimucronatus as belonging to D. pristis Hall. 

 Fritz Freeh (54:626) supposes this large mucronate form of the 

 Utica shale to be D. w h i t f i e 1 d i. Hall. A dietailed account of 

 all these forms will be given by the writer in another paper. 



Olimaoograptus bicornis and Dicranograp- 

 t u s r a m o s u s are, indeed, common to the Normans kill and 



^Diplograptus quadrimucronatus is restricted to the Utioa 

 shale, and for this reason, can not he adduced as connecting the Utica and 

 Normans kill shales; Diplograptus foliaceus, which is more 

 common in the Normans liill shale, ranges from the Chazy to the Lorraias 

 beds and hence is of no taxonomic value. 



