of Geological Peiiods, 279 



the Sapindacese, which we shall meet with again in the succeed- 

 ing stages ; they are there combined with Palms, Leguminosae, 

 and Tiliaceae, of which the generic affinities are still obscure, 

 but their physiognomy is that of corresponding plants under 

 the tropics. 



On the third horizon, which is known by the rich floras of 

 Monte Bolca, Skopan, Alum Bay, the sands of the Sarthe, and, 

 lastly, the gypsums of Aix, we may indicate, among many others, 

 the following genera : — 



Conifers : Araucaria, Juss. — A. Duchartrei, Wat. (Middle 



sands). 

 Palms : Flahellariaj Sternb. — F, Lamanonis, Brong. (Gypsum 



of Aix.) F. bolcensis, Mass. (Monte Bolca.) 

 Sabalites, Sap. — S. sp. n. (Sands of the Sarthe.) 

 MusACEzE : Musophyllum, Ung. — M. speciosum, Sap. (Gypsum 



of Aix.) 

 LiLiACE^ : Draccena, L. — Draccenites sepultus, Sap., D. Brong- 



niariii, Sap. (Gypsum of Aix.) 

 Ebenace^ : Diospyros, L. — B. rugosa, Sap. (Gypsum of Aix.) 

 Araliace^e. — Aralia, L. — A. primigeniaj Heer. (Bolca, Alum 



Bay.) A. multijida, Sap. (Gypsum of Aix.) 

 Stercultace^ : Sterculia, L. — S. labrusca, Ung. (Monte Bolca, 



Skopan, Alum Bay.) S. tenuilobajSaip. (Gypsum of Aix.) 

 Bombax, L. — B. sepultiflorum, Sap. (Aix.) 

 Sapindace^e : Sapindus,\j, — Sapindus pristinuSj Jleev, (Monte 



Bolca.) 

 JuGLANDEiE : Engelhardtiaj Lesch. — E. decora, Sap. (Gypsum 



of Aix.) 

 pAPiLioNACEyE : Brachypto'umj Benth. — B. {Micropodium) oli- 



gospermum, Sap. (Gypsum of Aix.) 

 DrepanocarpuSf C. Mey. — D. Dechampii, Mass. (Monte 



Bolca.) 

 MiMosE^ : Mimosa, Ad. — M. deperdita, Sap. (Gypsum of AiX.) 



Most of these genera, especially the more important ones, are 

 determined with certainty : — the genus Bombax by the observa- 

 tion of the corollas; the Aralia primigenia by that of the fruits. 

 The genera Engelhardtia, Brachijpterum, and Drepanocarpus 

 show theirs. Diospyros rugosa presents flowers and detached 

 calyces. All these forms (leaving out of consideration those 

 which are not exclusively tropical, such as the Laurinese, 

 IMyrsinese, llhamncse, Anacardiaccse, &c.) serve to characterize 

 the hottest regions of India, Africa, America, and Australia. 



Upon this horizon a true Araucaria makes its appearance for 



20* 



