Nature of the Imperfection — Questions as to its 



ARISING FROM WaNT OF CONTIxMUITY, 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 



