Ixiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



at the upper limits of the eocene or at the bottom of the miocene 

 deposits. This is covered by a succession of conglomerates, marls 

 and sandstones, fnll of the miocene types of the Superga, passing 

 upwards into the blue Sub-apennine marls and yellow sands. 

 Throughout these deposits the per-centage of fossil species is of so 

 mixed a character, that MM. E. Sismonda and Bellardi, after careful 

 examination, are unable to draAv a line between those termed miocene 

 and pliocene. The tertiary deposits near Bologna and the Tuscan 

 Maremma are noticed, the coal beds of the latter being referred to 

 an old miocene date, and the relations of these marine tertiary deposits 

 to the more modern terrestrial and freshwater travertines are traced. 



The chief object of this memoir, as previously observed, is to 

 establish a true equivalent of the eocene deposits in Southern Eu- 

 rope, and to show that the rocks so termed do not merely represent, as 

 suggested by M. Elie de Beaumont, the interval which has occurred in 

 Northern Europe between the upper part of the chalk, as there ex- 

 posed, and the commencement of the plastic clay series, but actually 

 constitute deposits effected at the same time with the eocene beds of 

 the Paris and London supracretaceous accumulations. Sir Roderick 

 Murchison particularly observes on the presence of species identical 

 with those of the Paris and London tertiaries in the nummulitic 

 rocks, and remarks that no characteristic fossil of the cretaceous 

 series has been continued into the nummulitic group, two or three 

 species of Gryphsea being alone common to the upper beds of the one 

 and lower deposits of the other. He examines the writings of the 

 geologists who have described the nummulitic accumulations of South- 

 ern Europe, and infers that the facts noticed by him and them are 

 in harmony. 



It would be impossible, in the necessary limits of an address of this 

 kind, to attempt any detailed observations upon the mass of infor- 

 mation brought forward by our colleague in this communication. Li 

 all such investigations, tracing great deposits of mineral matter over 

 large areas, it becomes of importance duly to consider the physical 

 conditions which may have obtained at different times over the whole 

 or parts of it. This we obtain by careful study of the lithological 

 character of the deposits themselves. Among the most striking geo- 

 logical features of the wide area noticed, is the mass of calcareous ac- 

 cumulations, which have been effected from the date of the great 

 Alpine limestone to the modern terrestrial travertines of Italy inclu- 

 sive. No doubt much of this calcareous matter may have been in 

 parts used over and over again, portions only of different dates re- 

 maining to show us what we seek, both as to the physical conditions 

 under which the deposits of different geological times in certain areas 

 were effected, and the life of the time, so far as can be inferred from 

 the remains of it entombed in such deposits. Nevertheless, regard- 

 ing it as a mass, the amount of calcareous matter in the region noticed, 

 and in the extension of the same deposits in Northern Africa and 

 away into Asia, shows a certain continuance of physical conditions 

 fitted for its production, which requires to be taken into account 

 when we regard the subject as a whole. The variations of these 



