EXPLANATION OF PLATE I 



All figures approximately natural size 



Fig. 1. Pitria dalli n. sp. An inner view of specimen of left valve p. 41 



Fig. 2. Pitaria dalli n. sp. - An outer view of specimen of left valve p. 41 



Fig. 3. Pitria dalli n. sp. An inner view of specimen of right valve p. 41 



Fig. 4. Pitria dalli n. sp. An anterior view of shell showing lunule p. 41 



Fig. 5. Ostraea lincolnensis n. sp. Inner view of valve p. 36 



Fig. 6. Ostraea lincolnensis n. sp. Outer view of valve p. 36 



Fig. 7. Crassatellites merriami n. sp. Outer view of right valve p. 36 



Fig. 8. Crassatellites merriami n. sp. Inner view of right valve p. 38 



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