PLATE 21 



Chonetes canadensis Billings 



Page 86 



1 Interior of a ventral valve with strong radial pallial sinuses 



2 Internal cast of ventral valve indicating a strong median septum 



3 Exterior of a distorted ventral valve showing the coarse median 



stria 



4 Interior of a portion of the dorsal valve 

 Locality. Misery stream 



Dalmanella cf. circularis (Sowerby) 



Page 83 



5 Exterior of a dorsal valve 



6 Interior of a dorsal valve 



7 Internal cast of a ventral valve 

 Locality. Jackman farm 



Rhipidomella musculosa Hall var. Solaris Clarke 



Page 88 



8 Exterior of a ventral valve 



9 Interior of a dorsal valve 



10, 1 1 Internal casts of ventral valves 



Localities. Figures 8, 10, n, Tomhegan point, Moosehead lake; 

 9, Jackman farm 



Hipparionyx proximus Vanuxem 



Page 88 



12 Internal cast of a ventral valve 



Locality. Cunningham's camp, near Matagamon lake 



Leptostrophia oriskania Clarke 



Page 87 



13, 14 Two specimens viewed from the ventral surface 

 Locality. Matagamon lake 



Leptostrophia magnifica Hall 



{See plate 20) 

 Page 87 



15 Exterior of a ventral valve 



Locality. Matagamon lake 



208 



