INTRODUCTION. 23 



examination have been obtained on the peninsula of Noursoak (70° 37' N.), 

 from beds of shale alternating with banks of sandstone, the whole over- 

 lying granite or primitive formation. One of the localities, that of Elkor- 

 fat, is 500 feet above that of Kome, but the plants are of the same kind. 

 The vegetable remains belong mostly to cryptogamous and gymnosper- 

 mous plants: 41 Ferns, 1 Marsilia, 1 Lycopod, 3 Equisetacece, 10 Cycadem, 

 21 Conifers, 6 Monocotyledons, and a single Dicotyledonous species. 



On the south side of the same peninsula of Noursoak, near Atane, at 

 an elevation of 650 feet above the sea, another lot of plant-remains, col- 

 lected also by the expeditions of Nordenskjold, and submitted to Prof. 

 Heer for examination, represents a Flora composed of far different elements. 

 It has 170 species: 3 Fungi, 31 Ferns, 1 Marsilia, 1 Selaginella, 1 Equi- 

 setum, 8 Cycadece, 27 Conifers, 8 Monocotyledonous, and 97 Dicotyledonous 

 plants. These, therefore, constitute more than one-half of the vegetation. 1 

 The celebrated author remarks, on the geological relation indicated by the 

 characters of the plants, that it is not possible to determine it positively, 

 as the plants of the Cretaceous are, as yet, too little known. But he admits 

 that the formation of Atane, considering its vegetable remains, is probably 

 referable to the lower Cenomanian. 



As will be seen in the examination made of the age of the Dakota 

 Group, from data shown in the table of distribution, its Flora seems to be 

 somewhat more recent than that of Atane, though the relationship is very 

 close. The general character of the plants does not greatly differ, but the 

 number of the dicotyledonous plants is much greater, amounting in the 

 Flora of the Dakota Group to more than five-sixths of the vegetation. 



In considering merely what is now known of the vegetation of the 

 Middle Cretaceous (the Cenomanian of d'Orbigny), the first appearance, 

 and especially the prodigious development, of the Dicotyledons seems the 

 more wonderful that it is not a local phenomenon, but is remarked in the 

 formations of the same age over the whole Northern hemisphere. We 

 cannot yet follow it in all the intervening land areas, but it has been traced 

 from Greenland to Vancouver Island to Canada, to Kansas, and Colorado, 

 and in Europe to Germany, therefore in about 40° N. latitude. 



1 These data are taken from Heer"8 " Groenland Flora," vol. vi, part 2. 



