TO CANADIAN MICRO-PALAEONTOLOGY. 



13. Leperditia balthica (Hisioger), viir. prim^va, (nov.). 



PI. 10, fig. IS. 



Length 3-3 (hinge-line 2-3), heiglit 2-3 mm. 



This small Leperditia occurs with Isochilina labellosa'm (\aiietoii Co., 

 Oatario. It was at first confused with the latter species; but, though 

 much of the same shape, and with no external markings, it has a true 

 Leperditian ventral edge, and is of large size. It is so much like L. 

 balthica in its outline that I venture to regard it as an early represen- 

 tative or predecessor of that species. 



14. Leperditia (sp.). AVoodcut, fig. 4. (Compare L. IIisinijeri, 



Schmidt). 



Fig. 4. Leperditia, cfr. L. Hiaingcri, Schmidt. Side view of the c-ast of the 

 interior of a left vaive ; much enlarged. 



Leperditia ? Quart. Journ. Geol. Soc, vol. XL VI, 1890, p. 553, No. 2. 

 Length 3*0 (hinge-line 2*3), height 1 -S mm. 



A single neat, somewhat compressed cast of the interior of the left 

 valve of a small Leperditia, without any characteristic feature except 

 its outline, the eye-spot, muscle-mark, and venti'al flange not being 

 shown. The greatest ventral curve is in the postero-ventral region. 

 The postero-dorsal angle is very distinct, over a limited ogee curve. 

 The front angle is broken off". 



The outline is like that of Leperditia Hisingeri, Schmidt, as figured 

 in the Ann. Mag. Nat. Uist., ser. 2, vol. XVII, 1856, ])1. 7, fig. 3, and 

 by Schmidt, Mdm. Acad. Imp. Sc, ser. 7, vol. XXX, Miscell. Silur., 

 1883, p. 14, pi. 1, fig. 0. This species may probably have had repre- 

 sentatives befoi-e the later Silurian period. 



In dark-coloured, micaceous, shaly mudstone, somewhat ferruginous; 

 Chazy Shales. Broad street, Ay liner, Quebec Province. Collected by 

 Mi". T. W. K. Sowter. 



