48 
POPULAR SCIENCE REVIEW. 
of clay, sandstone, and limestone either of mechanical, chemical 
or organic origin, the Cretaceous rocks are widely spread over 
the globe, occurring in Europe, Greenland, North and South 
America, New Zealand, India, and the Pacific Islands. Accord- 
ing to locality these rocks vary in mineral aspect, and indicate 
either deep or shallow water deposits, proximate lines of shore 
from which drift wood was carried into deeper water, or land- 
surfaces upon which grew for a long period a sufficiently luxu- 
riant vegetation to form moderate beds of coal, as in New 
Zealand, Vancouver’s Island, and other places. It is the nature 
of this vegetation we shall attempt to explain, as derived from 
the various localities where plant remains have been preserved. 
In the British area and adjacent parts of France the creta- 
ceous plants are very few. The Lower Greensand or upper 
Neocomian shows, however, that the land of the Wealden period 
was not entirely submerged, for with its marine shells are found 
the Wealden fern ( Lonchopteris Mantelli ), the Wealden Iguano- 
don, the cycadeous genera Yatesia and Mantellia , and some 
cones and stems of coniferse. 
In the overlying gault at Folkestone coniferous fruits have 
been found, referred to the genus Wellingtonia ( Sequoia ), and 
others more nearly related to that group of the section Pinea , 
the members of which are now associated with the Wellingtonias 
in the west of North America, than to any other members of 
the great genus Finns , which seems to point to the existence 
of a coniferous vegetation on the high lands of the upper 
cretaceous period, having a facies similar to that now existing 
in the mountains on the west of North America, between the 
thirtieth and fortieth parallels of latitude. No fossil referable 
to Sequoia has hitherto been found in strata older than the 
gault, and here on the first appearance of the genus we find it 
associated with pines of the same group, species of which now 
flourish by its side in the New World.* 
In the gault, upper green sand, and white chalk, besides 
coniferous fruits, fragments of coniferous > wood are occasionally 
found, the latter sometimes having perforations made by a 
species of Teredina. 
On the continent of Europe, however, rocks of Cretaceous age 
have in sundry localities yielded a more or less abundant land 
flora, distributed at different geological horizons from the lower 
Neocomian to the Danian or uppermost chalk. 
To the Urgonian or middle Neocomian belong the bituminous 
schists and sphserosiderites of Teschen and Wernsdorff in the 
* Carruthers, “ Geol. Mag.” vol. viii. p. 540. A. Gray, “Address,” 1872, 
p. 5. 
t Schenk, “Die fossilen Pflanzen der Wernsdorfer Schichten in den 
Nordkarpathen.” Palaeontographica. Bd. xix. 
