204 Point Levi Fossils, 



The structure of the tail is similar to that of both A, tardus 

 (Barrande) and A. glabratus (Angelin) but in these species the 

 median lobe of the head is smooth and consists of one plate only, 

 without furrows. 



It may be that the tail above figured belongs to a different 

 species, but even if that should be the case it is specially 

 distinct from A. tardus and A. glabratus, for these are both 

 smooth, while ours is striated like A. exsculptus (Angelin), and 

 besides the proportions of the parts are suflSciently different to 

 be of specific value, especially when the character of the surface 

 is taken into account. A. tardus and A. glabratus, both belong 

 to the upper part of the lower Silurian. A. exsculptus to An- 

 gelin's Region B, which is the upper division of the Primordial 

 Zone in Sweden. 



In Limestone, No. 1. 



Agnostus Orion. N. s. 

 Fig. 2. 



Description. — Length and breadth about equal, sub-circular, 

 convex a very narrow margin all round, glabella not quite two 

 thirds the whole length, very convex, a transverse furrow at one 

 third the length from the apex, a small triangular tubercle at 

 each side next the posterior edge; no tubercle visible on the top 

 of the 2;labella. A fissure from the apex of the glabella to the 

 anterior margin. Length two lines. 



This species only differs from A. 2)isifo7-mis as figured by Salter 

 in the 3rd Edition of Siluria by having the glabella proportion" 

 ally shorter. 



Limestone, No. 1. In No. 2 there are two specimens of an 

 Agnostus which resemble this species but more are required 

 to decide whether they are identical or not. 



Agnostus Canadensis. N. s. 

 Fig. 3.— a. b. 



Description. — Head, obtusely oblong, semi-oval ; width, a little 

 greater than the length ;, a concave border nearly as wide as the 

 glabella all round. Glabella in width, less than half the width 

 of the head, and in length, a little more than two-thirds the 

 length of the head ; a triangular tubercle on each side at the 

 neck, and a transverse furrow a little in advance of the raid- 



