LIST OF ILLUSTRATIONS 



Past and future of geology. rage. 

 Figs. 1, 2, 3. Relative proportion of (he imniber of .species of or^aniu retuaius 



in Great Britain 183, 184, 185 



Eartb-isothenus 11)1 



Eefractiox of sound. 



Fig. 1. Carbonic-acid lens 208 



2,3. Hydrogen lens 209 



4. Vental refraction 210 



5. Tberuial refraction - 214 



6. Refraction by cold 215 



International code of symbols for CHAins ok fke-ihstoric arciueology. 



Fig. 1. Cavern, souterraio, slieUer 225 



2. Menhir, pillar, standing stone 2"J5 



3. Dolmen , allee-converte 225 



4. Tumulus, mound 225 



5. Sepulture, buniau remains 225 



G. Camp, entrenchment, oppidum 225 



7. PalaOtte, pile-dwelling.. 225 



8. Discoveries, stations, hearths 225 



9. Mine, quarry, digging 225 



10. Cavern, grotto, natural shelter 220 



11. Grotto or soutcrrain, of hunum construction 22(5 



12. Natural sepulchral grot to 22G 



13. Artificial sepulchral grotto 220 



14. Subterraneous refuge 220 



15. True menhir or worked monolith 227 



10. Series of menhirs, alignment, avenue 227 



17. Cromlech or enceinte of stones '. 227 



18. Rocking stone 227 



19. Hollowed stones 227 



20. Sculptured or inscribed stones 227 



21. Monument, rune, (Pierre i\ legende) 227 



22. Dolmen, allec-couverte 227 



23. Dolmen under a tumu! us 227 



24. Dolmen over a tumulus 227 



25. Simple tumulus 228 



20. S.-pulchr.al mound 228 



27. Fortified tumulus 228 



28. Lojig barrow 228 



29. Tumulus inclosing a wooden chamber 228 



30. Tumulus surmounted by a monument 223 



31. Mardelle 228 



S. Mis. 115 25 



