NATURE OF THE IMPERFECTION QUESTIONS AS TO ITS 

 ARISING FROM WANT OF CONTINUITY, FROM LACK OF 

 PRESERVATION, FROM IMPERFECT COLLECTING. EX- 

 AMPLES LAND SNAILS, CARBONIFEROUS BATRACHIANS, 

 PALEOZOIC SPONGES, PLEISTOCENE SHELLS, DEVONIAN 

 AND CARBONIFEROUS PLANTS COMPARATIVE PERFEC- 

 TION IN THE CASE OF MARINE SHELLS, ETC. POSSIBLE 

 CAMBRIAN SQUIDS QUESTIONS AS TO WANT OF FIRST 

 CHAPTERS OF THE RECORD PRACTICAL CONCLUSIONS 



