474 CRETACEOUS AND TERTIARY FLORAS. 



their diversity. This is especially seen on comparing the plants of 

 this epoch from the following localities Greenland, Neidershoena in 

 Saxony, Moletin in Moravia, Quedlinburg and Blankenburg in the 

 Hartz, Halden in Westphalia, the sands of Aix, the Senonien of 

 Bausset, the Santonien of Fuveau in France, the North American 

 cretaceous flora of Nebraska, 1 and the Gelinden beds of Belgium, 

 which latter make a transition to the Tertiary. 



Thus the existence of floras well defined from each other is per- 

 haps more evident in the Cretaceous period than in any other epoch of 

 time. The Aix flora is said to include some 200 species, of which 

 67 are cryptogams, chiefly ferns, including species of Gleichenia, 

 Lygodium, Asplenium, and 10 other existing genera. There are numer- 

 ous coniferae, some hardly separable from Sequoia, species of Araucaria, 

 rare cycads, and Pandanus, while the familiar forms of the oak, fig, 

 and walnut are associated with several genera of Myrtacese, and 

 between 60 and 70 species of Protaceae, some of which belong to 

 the living genera Dryandra, Grevillia, Hakea, Banksia, Persoonia, 

 all Australian, and Leucospermum, now found at the Cape of Good 

 Hope. The American genera found in the Dacotah group are less 

 numerous. Professor Leo Lesquereux enumerates Liquidambar, Salix, 

 Populus, Betula, Myriea, Celtis, Quercus, Ficus, Platanus, Laurus, 

 Sassafras, Cinnamonum, Diospiros, Aralia, Magnolia, Leriodendron, 

 Menispermum, Negundo or Acer, Paliurus, Rhus or Juglans, and 

 Primus, an assemblage which includes all the essential arborescent 

 types of the existing American flora, except those marked by serrate 

 or doubly-serrate leaves. Very few of the species in these rocks have 

 the leaves serrate. No one could recognise a great break in time 

 between the Cretaceous and Tertiary rocks on the evidence of such 

 floras as these. 



The Lower Tertiary floras elaborated by linger, Heer, Ettingshau- 

 sen, and Mr. J. S. Gardner, F.G.S., are full of interest, as showing the 

 change in geographical distribution which took place with altered phy- 

 sical circumstances. We may illustrate this by citing the floras of 

 the London clay of Sheppey, and the immediately succeeding Bagshot 

 sands of Alum Bay. The Sheppey flora is chiefly known from the 

 fruits, that of Alum Bay chiefly from leaves. The Sheppey flora 

 comprises 72 genera and 200 species, of which 7 genera are 

 Gymnosperms, 18 genera Monocotyledons, and 43 Dicotyledons. 

 What at the present day would be termed a sub-tropical character, 

 is indicated by plants referable to the natural orders Musaceae, Pan- 

 danse, Cichonaceae, Loganiaceae, Sapotaceae, Ebenaceae, Biittneriaceas, 

 Sapindaceae, &c. Among the genera of the London clay are Sequoia, 

 Pinus, and Salisburia among conifers. The Agave, Sarsaparilla, Ban- 

 ana, Cardamoms, and Nipa which includes many species, are all found 

 on the north of Sheppey. There are about 15 palms, including 

 species of Areca, Iriartea, Livistona, Sabal, Chamaerops, Trinax. The 

 Oak and Walnut, Liquidambar, Laurel, Nyssa, and Euphorbiophyllum 



1 U.S. GeoJ. Surv. Territ., vols. vi. and vii. Lesquereux, Cret. and Tert. 

 Floras. 



