390 



Locality a7id Formation. — Cape Gasp^, in the upper part of the Lower 

 Helderberg group, in beds holding a mixture of Upper Silurian and Devo- 

 nian fossils. 



Collector. —VvoL R. Bell. 



CLASS UNCERTAIN. 



Genus Pasceolus, Billings. 



Fig. 366. 



Fig. 3ij7. 



Fig. 366. — P. Halli. From the Middle Silurian, Anticosti. 

 Fig. 367. — P. globosus, Trenton limestone, Ottawa. 



The fossils of this genus are of an ovate or globular form covered with 

 an integument of small polygonal plates (?) and with one or more circular 

 apertures. Two species are at present known to occur in the Silurian 

 rocks of Canada, both of which are above figured. 



jP. I£alU is of an ovate form, from one to two inches in length and 

 about one-fourth less, in width. At one end there is a narrow prolonga- 

 tion Avhich, most probably, constituted the pedicle by which the body was 

 attached to the bottom. No trace of any other point of attachment can 

 be seen ; and it is almost certain, therefore, that this smaller extremity is 

 the base. A little below the mid-height of the body there is a small cir- 

 cular elevation which appears to mark the place of an orifice ; but as the 

 integument is not preserved in this part, it cannot, at present, be posi- 

 tively determined whether there was an aperture here or not. All that 

 can be said is that there appears to have been an orifice where this eleva- 

 tion occurs. The specimens collected arc all casts of the interior, but of 

 the one figured a portion of the integument remains attached to the 

 matrix. It is about one-third of a line in thickness, of a translucent, 

 horny color, the surface covered Avith minute corrugated wrinkles just 

 visible to the naked eye. No sutures can be distinguished, and tlie form 

 of the plates can only be made out as so many obscure convexities on the 



