- 233 



GENERAL CONCLUSIONS 



The locality of Menât; of which schists constitute the object of this study, 

 is situated in the department ol" Puy-de-Dôme, in the North of the " Massif 

 Central " of France. 



We hâve examined the main collections which hâve been studied previously 

 and especially the one that Heer mentions in the volume third ofthe " Flora 

 Tertiaria Helvetiœ'\ Heer's opinion was chiefly based on the similitude ofthe 

 shapes and outlines with the types of Switzerland and many of his détermina- 

 tions were made from most incomplète samples. 



De Saporta, and some authors aller him. hâve based their opinion as regard 

 the âge of the Menât schists on the ampleness of the leaves which can be 

 seen in that place and would attribute those strata to the Aquitanian layer. 



This is a summary ofthe main conclusions drawn from our study. 



(i) The aspect ofthe whole ofthe végétation as regards the smallness or 

 ampleness of the leaves dépends upon the station. The way in which the 

 forms are grouped determins the âge to be assigned to the layers. 



(2) The authors hâve mentioned many types that are based on rather vague 

 déterminations : on the contrary a good number of the Menât species présent 

 an archaïc appearance. 



(5) That flora has, but, very few species simiJar to those of the *' Massii 

 Central" attributed to the Middie Tertiary. 



(4) The types of the Eocene inferior and even those of the Cretaceous supe- 

 rior hâve not vet disappeared at the period of the deposit Menât schists. 

 Those ot the Eocene middie and superior, as vvell as those of the Oligocène 

 inferior are very abundant : the more récent types belong to some forms that 

 ary very common. 



(5) A comparative study of the species of Menât and of the présent ones 

 permits to ascertain a strong proportion of types belonging to the warm zone. 



(6) The ftora of Menât appears therefore as representing the végétation 

 of a warm and damp région of forests in which some ancient types in way of 

 élimination hâve been preserved, when the northern types hâve not been 

 acquired and are only represented by archaïc samples. 



(7) We are therefore induced to place the flora of Menât on the bounds oi 

 the two periods with which it has the greatest analogy, viz. the Eocene and 

 the Oligocène. 



30 



