PLATE I 
Fig. 1. Whitella securiformis. Riviere des Hurons, province of Quebec. Type. 
Geological Survey of Canada. 
Fig. 2. Whitella complanata. Riviere des Hurons, province of Quebec. Type. 
Geological Survey of Canada. 
Fig. 3. Whitella goniumbonata. Riviere des Hurons, province of Quebec. 
Geological Survey of Canada. 
Fig. 4. Modiolopsis postplicata. Riviere des Hurons, province of Quebec. 
Geological Survey of Canada. 
Fig. 5. Orthodesma approximatum. Chambly village, province of Quebec. 
Geological Survey of Canada. 
Fig. 6. Clidophorus praevolutus. Two specimens, not types. Riviere des 
Hurons. Geological Survey of Canada. 
Fig. 7. Modiolodon poststriatus. One mile west of Vars, province of Quebec. 
Geological Survey of Canada. 
Fig. 8. Pholadomorpha chambliensis. Chambly village, province of Quebec. 
Geological Survey of Canada, No. 2039. 
Fig. 9. Cymatonota lenior. Riviere des Hurons, province of Quebec. Geo- 
logical Survey of Canada. 
Fig. 10. Caritodens demissa, Conrad. Riviere des Hurons, province of Quebec 
The terminations of the anterior ear and posterior wing are omitted. Geological 
Survey of Canada. 
Fig. 11. Rhytimya oehana, Ulrich. Chambly village, province of Quebec. 
Geological Survey of Canada. 
Fig. 12. Clidophorus praevolutus. Chambly village, province of Quebec. 
Geological Survey of Canada, No. 2079. 
Fig. 13. Clidophorus sp. Rome, New York. From collections of the New York 
State Museum at Albany, No. R-1232. 
Fig. 14. Cymatonota pholadis. Hall. Chambly village, province of Quebec. 
Geological Survey of Canada. 
Fig. 15. Orthodesma prolatum. Beach below Becanceur river, province of 
Quebec. Geological Survey of Canada, No. 2144. 
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