32 THE AMERICAN NATURALIST [Vol. XLIV 



etc., but so far as known no palms. Some, as Ailanthus 

 (imrrianm, pertain to genera now restricted to Asia. 



The determination of the age of the Florissant beds 

 has been a matter of some difficulty, notwithstanding the 

 large number of organisms preserved. Comparing the 

 flora with that of the European Tertiary, I have felt 

 satisfied that it should be referred to the Miocene, and 

 probably to the Upper Miocene. The resemblance to the 

 flora of (Eningen in Baden, known to be upper Miocene, 

 is most striking. Thus we have the following parallel 

 or representative species: 



Florissant. 

 Liquidambar convexum Ckll. 



Comptonia insignis (Lx.) Ckll. 



Porana tenuis Lx. 

 Acer florissanti Kirch. 



(Eningen. 

 Liquidambar europium A. Br. 

 Ulmus braunii Heer. 

 Comptonia ceningensis A. Br. 

 Porana azningensis A. Br. 

 Porana macrantha Heer. 

 Acer tricuspidatum A. Br. 2 



Manx- others could be cited. On the other hand, the 

 Florissant incense cedar, Heyderia or IAbocedrus colo- 

 radensis Ckll., is to be compared with //. salicornioides, 

 of the Lower Miocene of Radoboj in Croatia. The 

 Florissant redwood. Sequoia hwydeni (Lx.), is not related 

 to S. sfmihcrf/i Heer from (Fningen, but to S. langsdorfii 

 (Brgt.) Heer of the Swiss Lower Miocene; this species, 

 however, survived into the Upper Miocene in Italy and 

 Galicia. This 8. langsdorfii has been recognized in 

 America also from the Upper Cretaceous to the Miocene, 

 and some of the Florissant specimens have been referred 

 to it; but the identity of the plants from so many diverse 

 localities and horizons is questionable, and from Floris- 

 sant I think we have only one species, S. haydeni. 



The Sequoia and Libocedrus of Florissant are both 

 very closely related to their living California!! allies; so 



