THE CRETACEOUS FLORA. 
53 
whereas the new Forms, with their luxuriant flowers, which now 
began to characterise the vegetable world, required, in order to 
develope all the grandeur of their colours, a clear and sunny 
sky. The disappearance of sundry tropical and sub-tropical 
forms, that are met with in the older Cretaceous strata, has led 
Heer to the conclusion that difference of climate at different 
latitudes was now beginning to show itself ; and he calls atten- 
tion to the circumstance that this takes place synchronously 
with the development of the dicotyledonous plants in greater 
variety.” * 
The Cretaceous character of the strata containing coal and 
lignite at Vancouver’s Island and adjacent district was some 
years since noticed by Dr. Newberry, and these and their exten- 
sive development along the Pacific coast have been described 
by Dr. Hector. 
At Nanaino — where the coal has been largely worked, as on 
Newcastle Island — there are two seams, the first of which is 
about six feet in thickness, with sometimes a floor of fire-clay, 
but more generally of sandstone ; and the roof, consisting of 
the fine conglomerate bed, about sixty feet thick, on which 
rests the Douglas seam, with an average thickness of about 
four feet.f 
The coals and fossil plants of Vancouver’s Island were con- 
sidered at one time to be of Tertiary age, but this identifica- 
tion appears to have been made upon insufficient evidence. 
Among the fossil plants there is one, the Sequoia Reichenbachi , 
which is numerous in localities in the Cretaceous of Europe 
and in the Arctic regions. Interstratified with and overlying 
the beds of coal at Nanaino are strata containing great numbers 
of well-marked Cretaceous mollusks — Ammonites , Baculites , 
Ino ceramus, &c.i 
The most abundant North American Cretaceous flora is that 
of the Western Territories, collected from beds known as the 
Dakota group, by the labours of Dr. Newberry, and the geolo- 
gical survey under Dr. Hayden, and recently described by 
Professor Lesquereux.§ 
The Dakota group lies at the base of the Cretaceous series, 
and, with the associated Fort Benton group, is equivalent to 
the Cenomanian and Turonian of Europe ; overlying these are 
many hundred feet of strata, destitute of plants, referred to the 
upper chalk or Senonian, and above these are the remarkable 
lignitic beds or “ Transition Series ” of Dr. Hayden, which 
* “ Geol. Mag.” Nov. 1875, p. 529. 
t Hector, J. “ Quart. Journ. Geol. Soc.” vol. xvii. p. 433. See also 
Newbeny, “Proceed. Boston Nat. Hist. Soc.” 1863. 
X J. S. Newberry, “ American Journ. Science and Arts,” April 1874. 
§ “ The Cretaceous Flora.” Washington, 1874. 
