COASTS VISITED BY THE ARCTIC EXPEDITION". 591 



Genus Asaphus, Brongniart, 1822. 



Asaphus, sp., like A. tyrann/tts, Murch. Sil. Syst. t. 24, t. 25. f. 1. 



Asaphus tyrannus, Salter, Monogr. Sil. Trilobites, Pal. Soc. p. 149, 

 t. 21, t. 22. f. 5-12. 



Unfortunately only the pygidium or caudal shield has been left 

 upon a slab of limestone ; but no doubts are entertained as to the 

 genus, although only so small a specimen. It agrees in every respect 

 with the pygidia of small or young forms of Asaphus tyrannus and 

 Asaphus Powisii: the axis may be narrower than usual in those 

 species, being more uniform in width or diameter ; but the pleurae 

 and broad caudal fascia all tend to convince me that it is closely 

 allied to Asaphus tyrannus, although with us this is a Llandeilo form ; 

 indeed in Britain no species of Asaphus is known in the Upper 

 Silurian rocks. There seems much doubt as to the horizon at Cape 

 Louis Napoleon from which some fossils come ; we certainly have 

 Lower and Upper Silurian species in the series from this locality. 



Asaphus marginalis, Hall, Pal. N. Y. vol. i. p. 24, t. 4. fig. 5, 

 resembles this only in the narrowness of its caudal axis. 



Loc. Cape Louis Napoleon, 79° 38'. From Upper Silurian. 



Genus Calymene, Brongniart, 1822. 

 Calymene, sp. 



1 Calymene senaria, Conrad, Ann. Geol. Eeport, New York, 1841, 

 p. 49 ; Hall, Pal. New York, vol. i. p. 238, t. 64. f. 3, a-n. 



The cephalic portion of this species is wanting, and also much of 

 the caudal shield ; nevertheless I think I am right in referring it to 

 the Calymene senaria of Conrad. Hall obtained his specimen from 

 the Trenton series ; it is very closely allied to our Calymene Blumen- 

 bachii, or one of its many varieties ; twelve thoracic somites are dis- 

 tinctly preserved. The faceted pleurae cannot satisfactorily be made 

 out, the specimen being much weathered, and none of the cephalic 

 portion remains. The figure and description given by Hall (he. cit.) 

 for the American species agree better with our specimen than that 

 given by Salter in the Palaeontographical Society's Memoirs, t. 9. 

 figs. 6-11. Many forms of the variable Calymene Blumenbachii may 

 be mistaken for the specimen I have referred to Conrad's species. 



Loc. Dobbin Bay, lat. 79° 40' ; furnishing another instance of the 

 mingled condition or character of the series from this locality. 



Calymene, sp. 



Six thoracic segments with axis and pleurae of some species of 

 Calymene occur in the Silurian Limestones of Hayes Point, lat. 

 79° 42' : fragments of some unknown Crustacean (?) are associated 

 with it; these will be referred to in their places. If not Calymene, 



Q.J.G.S. No. 135. 2r 



