432 Fossils of the Chazy Lhnestcnc. 



■with all the angles and edges broadly rounded, there is a series 

 becoming more and more convex, until all trace of the anterior 

 slope is lost, while the two lateral slopes are only visible for a 

 short distance b-low the beaks. By taking the extremes, several 

 species might be made out of this one, but I am satisfied that 

 they would not in the end be sustained. 



The surface is sometimes nearly smooth, but usually it is 

 marked by concentric undulations of growth. I have not been 

 able to detect any minute concentric striae between the larger un- 

 dulations, and on only one of all the specimens that I have seen 

 are there any longitudinal striae, and these are only faintly indica- 

 ted on the cast of the interior. The specimens collected in the 

 Chazy limestone in the neighbourhood of Montreal are of a jet- 

 black colour and often exhibit a polished shining surface, but 

 those in the same rock in the valley of the Ottawa above Caril- 

 lon, are light brown. 



This species is closely allied to L. antiqua, (Hall) but is not 

 longitudinally striated. In the Potsdam Sandstone on Lots 21 

 and 22, in the 9th concession of the Township of Bastard, L. 

 antiqua occurs in vast abundance, and among the specimens col- 

 lected at that locality, there are a great many which have almost 

 exactly the same form as L. Belli, the only difference being the 

 longitudinal striae. 



I have also before me specimens from the Falls of St. Croix, 

 in Wisconsin, said to be the L. prima of the Potsdam, and these 

 also have the depressed pyramidal elevation, but are in outline 

 sub-orbicular or obscurely sub-pentagonal. The elongated form 

 sometimes referred to L. antiqua appears to me be L. acuminata, 

 (Conrad) and differs from all the above by being convex from the 

 beak all along the median line to the front. 



Dedicated to the late Rev. A. Bell of L'Orignal, an enthusiastic 

 geologist, from whose labours the science in this Province has 

 received much valuable aid. The beautiful collection of Canadian 

 Fossils bequeathed by him to the University of Queen's College, 

 Kingston, must always be of great service to the students of that 

 excellent institution. 



Locality and formation. — Island of Montreal ; near L'Orignal ; 

 Allumette Island. Chazy. Perfect specimens rare. 

 Collectors. — Sir W. E. Logan, J. Richardson, R. Bell. 



