346 



Prof. T. ]l. Jones on the 



Table of tlie Diairihation of the Silurian Leperditise, 



Arctic Regions. 



Wellington 

 Strait. 



/'Lower Helderberg 

 Group (Tentacu- 

 lite Limestone, 

 formerly included 

 in the Water- 

 J lime group). 



' Coralline Lime- 

 stone of Scho- 

 harie (Niagara 

 Group ?). 

 Onondaga Salt 



\^ Group. 



j Clinton Group ... 



J Medina Sandstone 



1 Oneida Conglo- 



\_ merate. 



^Hudson-River 



Group 



Utica Slate 



Trenton 

 stone .. 



Lime 



Black-River Lime- 

 stone 



\ Bird's-eje Lime- 

 stone 



Chazy Limestone. 



Calciferous Sand- 

 rock 



Quebec Group ... 



Potsdam Sand- 

 stone 



I 



I Leperditia 



I arctica, J. 



Beech ej' 

 Island . 



L. gibbera, J. 



Newfoundland. 



I 

 L. turgida, Billings ; 

 L. concinnula, B. ; 

 L. ven trails, B.\ 

 Primitia ? atlantica, 

 B. 1874 ; P. sim- 

 plex, y varr., J. 

 188L 



Canada. 



L. anticostiana, J. 



L. fabulites, C. ; L. 

 josephiana, J. ; L. 

 pauquettiana, J. ; 

 L. Billingsii, J. ; 

 L. louekiana, J. ? 



L. louekiana, J. 



L. louekiana, ./. ; 

 Isochilina gracilis, 

 J. 



L. canadensis, J. ; L. 

 amygdalina, J. ; 

 Isochilina Ottawa, 

 J. 



L. canadensis t, J. ; 

 L. Anna, J. ; Is. 

 Ottawa, J. ; Pri- 

 mitia leperditi- 

 oides, J. 



* There are several published forms which may prove to be Primitice 

 t Leperditia bivia, C. A. White, 1874, seems to be closely allied to 

 I These three forms are near allies of L. canadensis. 



