86 



CANADIAN MICRO-PALEONTOLOGY. 



Among the specimens from Eoche Eouge, Saskatchewan Eiver, be- 

 tween Cross Lake and Lake Winnipeg are — (1) several individuals of 

 Isochilina grandis, var. latimarginata, in a thin-bedded, yellowish lime- 

 stone, weathering white ; (2 and 3) the specimens figured on pi. xiii, 

 figs. 7 and 8, in a buff'-coloured, hard, rough limestone ; and in the 

 same limestone a more broadly-ovate Leperditia, not well exposed, but 

 perhaps like pi. xiii, fig, 1. The geological position of these specimens 

 is above those at the foot of the Grand Eapids. Collected by Mr. 

 Tyrrell, August 21, 1890. 



15. Leperditia phaseolus (Hisinger). Yar. guelphica, nov. 



Fig. 5. Leperditia phaseolus (Hisinger), var. guelphica, nov. Durham, Ont. 



Magnified j. 



Length 12-3 (hinge-line 8*6), height 9*3, thickness 5*3 mm. 



This is more ovate than figs. 7 and 8 on pi. xiii, being deeper from 

 above downwards, and rather more convex ; but the outline approxi- 

 mates to that of our figures above quoted, and to Kolmodin's pi. xix, fig. 

 5 b, as to the curvature of the ventral margin. 



In Guelph Limestone from Durham, Ontario, with L balthica, var. 

 guelphica. See page 80. 



16. Leperditia marginata, Schmidt. 

 PI. 10, figs. 6 a, b and c. 



Leperditia marginata, Schmidt. M4m. Acad. Imp. Sci. St.-P6tersbourg, Ser. 7, 



vol. XXI, No. 2, 1873, p. 19, figs. 29-31 ; Ibid. vol. XXXI, 

 1883, p. 18, pi. i, figs. 13-19. 



Length 6"& (hinge-line 5*), height 4*, thickness 3 mm. 

 Of this somewhat variable species, Schmidt's fig. 30 (1873) and fig. 



