or Macigno Formation in the South of Europe* 277 



limestone (Tuscany) ; lastly, at another locality on crystalline 

 rocks (Isle of Elba). And it is a truly remarkable thing, that 

 in Tuscany, where this formation is very greatly developed, it 

 is never Ibund associated with the nummulitico-hippuritic 

 limestone, — so independent is it of this latter. 



In the last place come the fossils to confirm the distinction 

 established. There has never been found, either in the ma- 

 cigno of Tuscany, or in that of any other locality, that I know, 

 any fossil belonging to the chalk formation of the north-west 

 of Europe. It is a well-known fact, that the principal organic 

 remains which characterize this formation are the Fucoids, 

 Now these are wholly wanting in the northern chalk forma- 

 tion ; and, a fact which deserves to be remarked, they are 

 also wanting in the southern nummulitico-hippuritic limestone. 

 On the contrary, the liudistcjc^ which are very abundant in this 

 last deposit, may be considered as entirely foreign to the first, 

 not a single individual having hitherto been found in it. The 

 same must be said of the ActionellcB, which habitually accom- 

 pany the Rudistce. M. d'Orbigny has shown that this latter 

 family (comprising in it the Cranice) occur in all the strata of 

 the chalk formation of Europe. If then it has no species 

 which represents it in the macigno, we must conclude that 

 this deposit does not belong to the cretaceous system. 

 Perhaps we might cite the Nummtdites^ which are common to 

 the macigno and to the limestone which is below it, and the 

 Ammonites, which have been taken from the macigno of Tus- 

 cany and Liguria ; but, without regarding the extreme rarity 

 of these fossils in the macigno, can it be affirmed that the spe- 

 cies are the same as those which we find in the nummulitic 

 limestone? No one can assert this*. 



We may then conclude, — 



1st. That the macigno has different mineralogical charac- 

 ters from those of the chalk. 



2nd. That it is superposed on the nummulitico-hippuritic 

 limestone, the upper part of which is connected with the white 

 chalk of the north of Europe. 



3rd. That it does not contain any fossil of the northern 

 chalk, but that it contains Fucoids^ absent in the latter as well 

 as in the southern nummulitico-hippuritic limestone. 



All the facts which I have here detailed appear to me to 



* The Nummulitesof the cretaceous Hmestone of Italy are ordinarily of 

 a large size, and resemble the Nummiilites of Peyrehorade in the Pyrenees, 

 which are figured in Lyell's Elements of Geology (cretaceous group). Of 

 this nature are the species which I have found in the Gargano, and those 

 which M. Pareto cites in the limestone of Mortola, in Liguria. On the 

 contrary, the Nuninuilites which have hitherto been found in the macigno 

 are iimch smaller. — (Note by M. Pilla.) 



