212 THE GEOLOGICAL HISTORY OF PLANTS. 



Between 1870 and 1873 my attention was turned to 

 the two subfloras intermediate between those of the Devo- 

 nian and the coal-formation, the floras of the Lower 

 Carboniferous (Subcarboniferous of some American geol- 

 ogists) and the Millstone Grit, and in a report upon 

 these * similar deductions were expressed. It was stated 

 that in Newfoundland the coal-beds seem to belong to 

 the Millstone Grit series, and as we proceed southward 

 they belong to progressively newer portions of the Car- 

 boniferous system. The same fact is observed in the 

 coal-beds of Scotland, as compared with those of Eng- 

 land, and it indicates that the coal-formation flora, like 

 that of the Devonian, spread itself from the north, and 

 this accords with the somewhat extensive occurrence of 

 Lower Carboniferous rocks and fossils in the Parry Islands 

 and elsewhere in the arctic regions. 



Passing over the comparatively poor flora of the earlier 

 Mesozoic, consisting largely of cycads, pines, and ferns, 

 and as yet little known in the arctic, and which may 

 have originated in the south, though represented, accord- 

 ing to Heer, by the supposed Jurassic flora of Siberia, we 

 find, especially at Kome and Atane in Greenland, an in- 

 teresting occurrence of those earliest precursors of the 

 truly modern forms of plants which appear in the Creta- 

 ceous, the period of the English chalk and of the New 

 Jersey greensands. There are two plant-groups of this 

 age in Greenland ; one, that of Kome, consists almost en- 

 tirely of ferns, cycads, and pines, and is of decidedly 

 Mesozoic aspect. This is called Lower Cretaceous. The 

 other, that of Atane, holds remains of many modern tem- 

 perate genera, as Populus, Myrica, Ficus, Sassafras, and 

 Magnolia. This is regarded as Upper Cretaceous. Eest- 

 ing upon these Upper Cretaceous beds, without the inter- 



* "Fossil Plants of Lower Carboniferous and Millstone Grit Forma- 

 tions of Canada," pp. 47, ten plates, Montreal, 1873. 



