348 Count Gaston de Saporta on the Temperature 



which appeared to be absent from the last floras that we have 

 passed in review. The following would be the enumeration of 

 these genera, assuming as well founded presumptions suggested 

 by a nearly definitive examination : — 



Alnus : two species, one modelled on the type of Alnus cordifolia, Ten., 



and the other on that of A. glutinosa, Gaertn. 

 Betula : a species analogous to B. lenta, Linn. 

 Dryophyllum, Deb. : three species analogous to certain species of Quer^ 



cus, Castanea, and Castdnopsis. 

 Ulmus : a very distinctly characterized species. 

 Populus : a species analogous to P. heterophylla, Desf. 

 Salix : two species analogous to Salix fragilis, Linn., and amygdalintty 



Linn. 

 Hedera : a species reproducing the type of H. helix, var. hibemica. 

 Cornus : a species analogous to C officinalis, Lieb. 

 Juylandites : several species, one of them not far from J. regia. 



This group is remarkable for its conformity with the pre- 

 (ieding data. Most of the genera the existence of which in the 

 last place was ascertained reappear ; and we remark no alteration 

 in their physiognomy, except that which results from the aspect 

 of the vegetation of which they form a part — that is to say, a 

 development of the foliaceous limb, peculiar to most of the plants 

 of Sezanne. It appears from their examination that the period 

 at which they lived, or perhaps only the locality where they 

 grew, favoured in them this expansion of the appendicular 

 organs, which contrasts so strongly with the stunted and coria- 

 ceous forms of the period of the gypsum of Aix. However this 

 may be, and notwithstanding the doubts which may still at- 

 tach to some of the determinations indicated by me, most of 

 these genera appear to me at present to be legitimately deter- 

 mined, so much do they approach the corresponding existing 

 types. I will indicate Alnus, Ulmus, Salix, Populus, Hedera, 

 and Cornus as those the unexpected existence of which at so 

 distant a period appears to me best demonstrated. 



Still further on, in the Upper Cretaceous period, the existence 

 of European genera has not been ascertained, except in a very 

 vague manner. The investigations are too recent and the ob- 

 servations too rare to inspire complete confidence. I think, 

 therefore, that the Carpinites, Acerites, and Juglandites of this 

 period must be subjected to a fresh examination before they can 

 be accepted as corresponding with types really allied to those 

 from which their denomination has been derived. Nevertheless 

 I have lately had in my hands some impressions from the Upper 

 Chalk of Halden, in Westphalia, resembling the genus Alnus in 

 several details of form and venation ; the Dryophjlla of Aix-la- 

 Chapelle have too close analogies with the Cupuliferse to be 

 quite foreign to that group; and we must also mention the 



