IXX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



this special labour. The figures are exquisite. The fifth part ap- 

 peared in 1853, and contained monographs of the species o? Itanella 

 and Murex (6 of the former and 43 of the latter genus). When 

 this work is completed we shall be in a better condition than ever for 

 deciding upon the vexata qua:stio concerning the limits of the middle 

 tertiaries. From the materials already before us we may obtain fore- 

 shadowings of the conclusion, and it may not be undesirable to offer 

 a few remarks suggested by the facts recorded by Dr. Homes ; in other 

 words, by the fossil species he has so well described and carefully 

 elucidated. 



As far as the work has progressed, the genera monographed are 

 canalicrdated Gasteropoda ; well-marked types, that are not likely to 

 mislead, belonging to as many as 24 genera. Now, in looking over 

 the lists of species in each, several points strike our attention, viz. 

 1st, the great development of species in certain tropical genera, or 

 genera in the main tropical, such as Conus (19 species), Cyprsea (10 

 species), Mitra (13 species), Terebra (8 species), Murex (43 species), 

 Ranella (6 species) ; 2nd, the fact that the species of the more ex- 

 tensive genera are mainly extinct ; 3rd, the fact that a considerable 

 number of existing moUusks, characteristically Mediterranean, are 

 present in this fauna ; 4th, the presence of very few, scarcely any, 

 existing forms not Mediterranean ; 5th, the fact that whatever Celtic 

 forms are present, such as CyprcBa europea, Erato Icevis, Nassa ia- 

 crassata, Chenopus pes-pelecani, axi& Murex erinaceus, they are shells 

 common to the Mediterranean and Celtic faunas, and therefore most 

 probably original members of the former ; Oth, the very large pro- 

 portion of species common to tertiaries in the north of Italy and south 

 of France ; 7th, the small number of references to the Touraine 

 Faluns, though those that occur are of considerable significance ; 8 th, 

 the small number and doubtful character of the identifications with 

 eocene species. This fauna seems as it were to have been the cradle 

 of the existing Mediterranean fauna, but in the main to have been 

 characteristic of the arms of a great previous Mediterranean, ivJiose 

 main centre was tropical, though not a portion of the Indo-Pacific 

 provinces of our times. It seems to have had no northern communi- 

 cations, at least in the direction of Austria. Its tropical character is 

 not derived at all from either the presence of eocene species or from 

 the stamp of an eocene fades. Some great inteiTention of different 

 physical conditions over a vast area must have separated its epoch 

 from the latest eocene sera. It is decidedly not the fauna of the so- 

 called lower miocene. A well-worked list of more than 150 species 

 warrants the suggestion of these provisional considerations. 



The search after and description of fossil plants has been actively 

 prosecuted on the continent, and not a few memoirs, several of them 

 beautifully illusti'ated, have appeared during the year. As contribu- 

 tions of facts towards a future understanding of Fossil Botany, these 

 papers and figures are welcome and valuable ; but as palseontological 

 data for the service of the geologist, the use and appreciation of them 

 requires the greatest judgement and caution. The vegetable unit in 

 lists of extinct bcino-s is of far inferior value to the animal unit, and 



