Xll PREFACE, 



found that Signer 0. G. Costa had examined the ter- 

 tiary fossils which I had sent to him from different 

 parts of Sicily, and declared them to be for the most 

 part of recent species. I then bent my course home- 

 ward, seeing at Genoa, Professor Viviani and Dr. Sasso, 

 the last of whom put into my hands his memoirs on 

 the strata of Albenga (see vol. iii. p. ICG), in which I 

 found, that, according to his list of shells,, the tertiary 

 formations at the foot of the maritime Alps contained 

 about 50 per cent, of recent species. 



.1 nejctbre-visited Turin, and communicated to Signor 

 JJpnelli the result of my inquiries respecting the ter- 

 tiary beds of the south of Italy, and of Sicily, upon 

 which he kindly offered to review his fossils, some 

 of which had been obtained from those countries, and 

 to compare them with the Subapennine shells of 

 northern Italy. He also promised to draw up imme- 

 diately a list of the shells characteristic of the green- 

 sand of the Superga, and common to that locality and 

 Bordeaux, that I might publish it at the end of my 

 second volume; but the death of this amiable and 

 zealous naturalist soon afterwards deprived me of the 

 benefit of his assistance. 



I had now fully decided on attempting to establish 

 four sub-divisions of the great tertiary epoch, the 

 same which are fully illustrated in the present work. 

 I considered the basin of Paris and London to be the 

 type of the first division; the beds of the Superga, of 

 the second ; the Subapennine strata of northern Italy, 



