text:  Although we are far from being able to demonstrate geologically an insensible transition from the Eocene to the recent _Fauna_ yet we may affirm that the more we enlarge and perfect our survey of Europe the more nearly do we approximate to such a continuous series and the more gradually are we conducted from times when many of the genera and nearly all the species were extinct to those in which scarcely a single species flourished which we do not know to exist at present