242 THE FLORA OF THE DAKOTA GKOUP. 



Of the Ulmea? no remains lui\e as yet l)een observed in the Ceno- 

 ituiuian, but Heerlias deserilied leaves of Phuiera from Patoot, and Dawson 

 records a frag-meiit (h)ubtfally described as Uhnns diibia, from the Upper 

 Cretaceous of Vancouver Ishmd. As Uhnus leaves are found al)undantlvin 

 the Tertiary measures of both continents, three species having been already 

 described from Suzanne by Saporta, it is probable that the presence and 

 orig-in of the g-enus may be recognized by further researches in the fossil 

 remains of the Dakota Gi'oup. 



Comparatively few fossil remains of the division Gamopetahv, have as 

 yet been tbuud in the Cretaceous. This is easily accounted for by the 

 mostly herbaceous nature of the pla'nts which compose it; the Compositse, 

 for example, the Rubiacese, Solanace», Labiatse, Scro^jhularinete, Primii- 

 laceJB, etc., are all plants of soft tissues that are rapidly destroyed by 

 maceration. Of the few tribes or families entirely or partly composed of 

 woody plants like the Loniceree, Oleacea', Ebenacepe, Ericacea?, etc., abun- 

 dant fossil remains are found in the IMiddle and Upper Cretaceous of 

 Greenland and of North America. 



In the Caprifoliacese numerous leaves of four species of Yilim-num of 

 the types of the li^^ng• V. nudum Linn., of L. Jantanoidas Michx., and V. 

 elUpticum Hook., have been described from the Dakota Group. None of 

 this genus has been as yet recognized in the flora of the schists of Atane, 

 l)ut three species are described by Heer from Patoot, which are also typic- 

 ally allied to some of the species composing* the present flora of the United 

 States; and another is represented by leaves and seeds in the Upper Cre- 

 taceous of Montana. From the Laramie Groujj twent}'-two species of 

 Viburnimi are recorded, two of them described by Dr. Newberry, eleven 

 by Prof Ward, and the others by myself, with still four species from the 

 Tertiary of the Bad Lands, two of them recognized also as in the Laramie. 

 All have a more or less marked degree of affinity with species of the pres- 

 ent flora of North America. Indeed, from the numerous representatives 

 of Vi])urnum in oiu- ancient and li\-ing flora, the g'enus a})pears to be 

 inostly iVmerican, for in Europe nine species only are described as fossil, 

 of whi(-h number three are from the Upper Cretaceous of Gelinden, one 

 from that of Westphalia, and six from the Tertiary, counting one described 

 from Sezanne. The relative proportion is preserved in the flora of our 

 epoch, for while three species only of Vilmrnnm are known in Europe we 

 have twelve in the North iVmerican flora, all except one inhabiting the 

 Atlantic slopes. 



