i562 NEW YORK STATE MUSEUM 



While the Dicellograptus fauna occurs only in the Appalachian re- 

 gion, Canadian basin and the far west and Pacific region, but not 

 east of the Mississippi, Diplograptus amplexicaulis 

 is also found in the Trenton of central New York (Middleville, 

 Trenton Falls) and in the Lorraine beds of northwestern New York 

 (Tariu), and in Iowa (J. F. James, loc. cit.). The fauna found by 

 Ami associated with the Dicellograptus fauna in the Quebec 

 region and the fauna of the conglomerate beds of Moordener 

 kill and Kysedorph hill, are different in strong features from the 

 Trenton of the rest of New York and the states directly south- 

 west of it. Here is the genus C h r i s t i a n i a , which has not 

 been found in the Lower Siluric of North America, but lived at 

 that era in European waters, the Bohemians genus P a t e r u 1 a , 

 which is well represented in the Normans kill shales and which 

 besides has been found only in Canada and is therefore restricted 

 to the continental margin; the trilobite genera Agnostus, 

 Aeglina (rediviva Barr. ?), A m p y x, D i o n i d e (?), ob- 

 served by Ami with the Normans kill graptolites, and the genera 

 A m p y X and Kemopleurides in the conglomerate bed of 

 Eysedorph hill, all forms which had apparently become extinct in 

 Ihe typical Trenton of New York, but continued to live in Europe. 

 Furthermore, as the Normans kill graptolite fauna has been 

 found by Lapworth to be an exact correlate of a European grapto- 

 lite zone, the conclusion seems to be unavoidable that the Nor- 

 mans kill or Dicellograptus fauna was foreign to the American 

 continental platform east of the Mississippi but was at home in 

 the oceanic basins of lower Trenton time and entered North 

 America along the eastern continental shelf. 



The middle Trenton shales of south Troy and Watervliet are, 

 by the occurrence of Diplograptus amplexicaulis, 

 ^nd Proetus parviusculus, connected with the Trenton 

 of Trenton Falls and the eastern Mississippi basin. 



The Utica graptolite fauna is again fully represented in Europe, 

 and quite certainly entered the North American continent 

 from the northeast, as asserted by Matthew (47) and the writer 

 (55). Perhaps, as suggested by Freeh (54. 2:100) the highroad 



