\\y2 NEW YOHK STATE MLSRUM 



Soiiio ntlit'r oliservaiioiis iiiaii*rialiv support iln^^ cuuclusioii. 

 Foioiuost of these is the oecurrenoe of C 1 i in a e o jjc r a p t ii s 

 s c li a r e n b e r g i iu the bhuk limestone. This jrraptolite, as 

 already reniarkiHl in another i)aper, is a tyjMcal form of the 

 lower and upjK'i- IMcellojjrai^tns zones in Canada, and of tin* 

 eorrespondinjr beds in Great Kritain, and is in New York 

 restricted to the lower Dicellojri'aptn^ zone or Normans kill 

 shale. As the eonjrlomerate bed is intercalated in this shah', 

 it is rvidcnt that the formation of the conjrlonuM-ate and 

 of tho shale are. «;ci»!ojii(aIly speaking, conlcmporaneous, aiitl, 

 as this j;:rai»tolite of snmll vertical ranjre occurs ahso in the black 

 limestone pebbles, the formation of that limestone must also be 

 nearly contemporaneous with, or, more exactly speakinjr, precetle 

 the formation of the conglomerate within the same subdivision 

 of the Trenton limestone epoch. 



The formation of that part of the Normans kill shale lyinj; 

 below the conglomerate bed, and of the black Trenton limestone 

 have, in the writer's opinion, been synchronous and goinu «>n in 

 adjacent regions, the black limestone representing the limestone 

 facies corresponding to the shaly Normans kill graptolite facies. 

 The remarkable coincidence of the existence of numerous 

 faunistic elements, strange to the continental Trenton of ,Ncuth 

 America, in both the shales and the black limestone, will In- 

 further discussed in the next section, but may be mentioned here 

 as additional argument in favor of the equivalency of the faunas 

 of the Normans kill shales, and of the black Trenton limestone 

 of the conglomerate.- 



Faunistic difference between the lower Trenton of New York and 



the west 

 In a previous paper the writer has already discussed the dif- 

 ference in sedimentation and fauna between the lower Tren- 

 ton as represented by the Normans kill graptolite shales of the 

 Appalachian region and lower Canada and the lower Trenton 

 limestone of the regions farther west. 



