FOSSIL BOTANY. 241 



4. Fossil Conifers are found in the form of stumps, 

 logs, leaves, and fruits. Tiiey were very unlike the ordi- 

 nary Conifers of temperate climates. They resembled more 

 or less the tropical Araucaria, the broad-leaved Chinese 

 Salisburia (Ginko), or the curious two-leaved African 

 WelvdtscMa. A very interesting genus is that of Cordaiies. 

 It had a straight trunk, sometimes sixty to seventy feet 

 long, and was clothed with long, strap-shaped leaves. 



204. In the early part of the Reptilian Age (during 

 the Triassic and Jurassic Periods) the Flora differed from 

 the preceding age mainly in the enormous development 

 of the Gymnosperms. These, — the Cycade (appearing now 

 for the first time) and Conifers, — together with the Tree- 

 Ferns, constituted the forest vegetation. There were also 

 new species of Ferns and Equiseta. Diatoms and Desmida 

 (division ZygoaporecB) were abundant. But it is in the 

 latter part of this age (during the Cretaceous Period) 

 that the greatest change took place. The Angiosperms 

 for the first time make their 

 appearance, and field and 

 forest began to assume a 

 somewhat modern aspect. 

 Such modern genera as the 

 Oaks, Maples, Willows, Sas- 

 safras (Fig. 346), Dog-wood, 

 Hickory, Beech, Poplar, Li- 

 riodendron. Walnut, Syca- 

 more, Laurel, etc., were 

 each represented by one or 346 



more species. The families to which the Angiosperms 

 belonged are as follows : 



Fig. 346, Sassafras aralio^sis (Reptilian Age). 



16 



