EXPLANATION TO PLATE 3. 



(Sliowini; the development of the shell and its spinosity.) 

 POWELL RIVER. 



Figs. 1-2. Lot 41. Group!. Drvden, Va. Enlarged 1/2. 



Fig. 3. Lot 45. Group 1. Olinger, Ya. Natural size. 



Figs. 4-5. Lot 41. Group 1. Dry den, Va. Natural size. 



Figs. 6-9. Lot 45. Group 1. Olinger, Va. Natural size. 



Figs. 10-11. Lot 38. Group 4. Sliawanee, Tenn. Natural size. 



Figs. 12-14. Lot 28. Group 5. Powell River P. O., Tenn. Natural size. 



Fig. 15. Lot 29. Group 5. Greens Ford, Tenn. Natural size. 



Fig. 16. Lot 30. Group 5. Agec, Tenn. Natural size. 



CLINCH RIVER 



Figs. 17-18. Lot 11. Group 7. St. Paul, Va. Natural size. 



Fig. 19. Lot 11. Shell No. 93. St. Paul, Va. Natural size. 



Fig. 20. Lot 51. Shell No. 33. Group 8. Fort Blackmore, Va. Natural size. 



Figs. 21-22. Lot 169. Group 8. Crafts Ferry, Va. Natural size. 



Fig. 23. Lot 165. Group 8. Crafts Ferry, Va. Natural size. 



Figs. 24-42. Lot 51. Group 8. Fort Blackmore, Va. Enlarged 1/2. 



Figs. 43-44. Lot 17. Group 10. Kyle Ford, Tenn. Natural size. 



IIOLSTON RIVER SYSTEM. 



Figs. 45-48. Lot 86. Group 15. Curry Ford, Tenn. Natural size. 

 Figs. 49-50. Lot 85. Group 15. Hord Ford, Tenn. Natural size. 



Figs. 51-67. Lots 97 and 98. Group 15. Chissolms Ford, Tenn. Figs. 51-56, enlarged 1/8. 

 Figs. 57-62, enlarged 1/16; and Figs. 63-67, natural size. 

 98 



