282 On the Temperature of Geological Periods. 



with comes from the schists of the valley of Larguer, near Ma- 

 nosque ; it consists of a coriaceous fruit of large size, dehiscent, 

 with the valves open and spread out, and. the resemblance of 

 which to those of Campsiandra angustifotia, Benth. (a scarcely- 

 known Brazilian species), is truly surprising. The genus 

 Brachjpterum reappearing, the Swiss Pterocarpus Fischeri, and 

 several Acacice, besides various Csesalpiniese and Dalbergieae, 

 form a total the tropical physiognomy of which cannot be over- 

 looked. 



The sia;th horizon is principally represented by the rich floras 

 of Parschlug and CEningen. Here the lowering of the tempera- 

 . ture begins to be sensible ; but we can still indicate the following 

 as tropical types: — 



Palms: Calamopsis, Heer. — C bredana, Heer. (CEningen.) 

 ' GoNVOLVULACE^ : Porana, Burm. — P. ceningensisy Al. Br., 



P. macrantha, Heer, P. inaquiloba, Heer. (CEningen.) 

 SAPiNDACEiE : SapinduSjlj. — S. falcifolius, Al.Br. (CEningen.) 

 MiMOSE^ : Acacia, Neck. — A. ceningensis, Heer. (CEningen.) 

 A. parschlugiana, Ung. (Parschlug.) 

 Mimosa, Ad. — A. palceogcea, Ung. (Parschlug.) 



The tropical element was therefore far from being banished 

 from the middle of Europe at the epoch of Cblningen, the 

 temperature of which has been approximately estimated by 

 M. Heer at 18° C. ( = 64°-4F.). Nevertheless, starting from 

 this time, the depression must have been rapid and continuous. 

 In fact our seventh horizon, corresponding to the Pliocene, 

 and well known by the floras of Gleichenberg in Styria, of 

 Senegaglia and the Val d^Arno in Italy, and of Schlossnitz in 

 Silesia, no longer contains any really tropical types. I can 

 hardly cite the Oreodaphne Heeriij Gaud., nearly identical with 

 O.foetens of the islands of Madeira and the Canaries, where the 

 latter species is now isolated, whilst the rest of the genus is 

 American and prefers the tropical regions of that continent. 



Moreover, the subtropical types had declined with almost 

 equal rapidity ; the laurels, figs, Ebenacese, and Myrsinese had 

 likewise diminished in number and importance. Of these, 

 however, the Pliocene period still presents some examples; but 

 our eighth and last, or quaternary horizon, no longer includes any 

 genera but those belonging to the northern temperate zone. 



[To be continued.] 



